Analysis of gastric fluid in preterm newborns supports the view that the amniotic cavity is sterile before the onset of parturition: a retrospective cohort study

OBJECTIVES

To compare the frequency of Ureaplasma-positive gastric fluid (GF) cultures based on the cause and mode of delivery in preterm newborns.

METHODS

This retrospective cohort study included women with a singleton pregnancy who delivered prematurely (between 23+0 and 32+0 weeks of gestation, n=464) at a single university hospital in South Korea. The newborns' GF was obtained on the day of birth via nasogastric intubation. The frequency of Ureaplasma spp. in GF cultures was measured and compared according to the cause and mode of delivery.

RESULTS

Ureaplasma spp. was detected in 20.3 % of the GF samples. The presence of Ureaplasma spp. was significantly higher in the spontaneous preterm birth group than in the indicated preterm birth group (30.2 vs. 3.0 %; p<0.001). Additionally, Ureaplasma spp. was more frequently found in the vaginal delivery group than in the cesarean delivery group, irrespective of the cause of preterm delivery [indicated preterm birth group (22.2 vs. 1.9 %, p=0.023); spontaneous preterm birth group (37.7 vs. 24.2 %, p=0.015)].

CONCLUSIONS

Ureaplasma spp. were found in 20.3 % of the GFs. However, only 1.9 % of newborns in the indicated preterm birth group with cesarean delivery had a Ureaplasma-positive GF culture.

A multivariable prediction model for intra-amniotic infection in patients with preterm labor and intact membranes including a point of care system that measures amniotic fluid MMP-8

OBJECTIVES

Among patients with preterm labor and intact membranes (PTL), those with intra-amniotic infection (IAI) present the highest risk of adverse perinatal outcomes. Current identification of IAI, based on microbiological cultures and/or polymerase chain reaction amplification of the 16S ribosomal RNA gene, delay diagnosis and, consequently, antenatal management. The aim to of the study was to assess the performance of a multivariable prediction model for diagnosing IAI in patients with PTL below 34.0 weeks using clinical, sonographic and biochemical biomarkers.

METHODS

From 2019 to 2022, we prospectively included pregnant patients admitted below 34.0 weeks with diagnosis of PTL and had undergone amniocentesis to rule in/out IAI. The main outcome was IAI, defined by a positive culture and/or 16S ribosomal RNA gene in amniotic fluid. Based on the date of admission, the sample (n=98) was divided into a derivation (2019-2020, n=49) and validation cohort (2021-2022, n=49). Logistic regression models were developed for the outcomes evaluated. As predictive variables we explored ultrasound cervical length measurement at admission, maternal C-reactive protein, gestational age, and amniotic fluid glucose and matrix metalloproteinase-8 (MMP-8) levels. The model was developed in the derivation cohort and applied to the validation cohort and diagnostic performance was evaluated. Clinical management was blinded to the model results.

RESULTS

During the study period, we included 98 patients admitted with a diagnosis of PTL. Of these, 10 % had IAI. The final model included MMP-8 and amniotic fluid glucose levels and showed an area under the receiver operating characteristic curve to predict the risk of IAI of 0.961 (95 % confidence interval: 0.860-0.995) with a sensitivity of 75 %, specificity of 93.3 %, positive likelihood ratio (LR) of 11.3 and negative LR of 0.27 in the validation cohort.

CONCLUSIONS

In patients with PTL, a multivariable prediction model including amniotic fluid MMP-8 and glucose levels might help in the clinical management of patients undergoing amniocentesis to rule in/out IAI, providing results within a few minutes.

Intra-amniotic Candida albicans Infection Treated With Liposomal Amphotericin B With a Successful Neonatal Outcome

Intra-amniotic infection with Candida species is an uncommon but severe condition with high fetal morbimortality and no established clinical guidelines for its management. We report a Candida albicans intra-amniotic infection diagnosed in a 25-week pregnant woman, successfully treated with high-dose liposomal amphotericin B. Pregnancy was prolonged until 30 weeks, and despite persistently positive Candida cultures in amniotic fluid, a healthy newborn was delivered without evidence of systemic infection. Amphotericin concentration was determined at birth, revealing levels over 30 times higher in mother's and cord blood than in the amniotic fluid, probably explaining the clinical protection despite failure in obtaining fungal clearance.

Intra-amniotic infection and/or inflammation is associated with fetal cardiac concentric hypertrophy and diastolic dysfunction in preterm labor and preterm prelabor rupture of membranes

BACKGROUND

Preterm delivery is associated with cardiovascular remodeling and dysfunction in children and adults. However, it is unknown whether these effects are caused by the neonatal consequences of preterm birth or if these are already present in utero.

OBJECTIVE

We evaluated fetal cardiac morphology and function in fetuses of mothers admitted for preterm labor or preterm prelabor rupture of membranes and the association of these changes with the presence of intra-amniotic infection and/or inflammation.

STUDY DESIGN

In this prospective cohort study, fetal echocardiography and amniocentesis were performed at admission in singleton pregnant women with preterm labor and/or preterm prelabor rupture of membranes between 24.0 and 34.0 weeks' gestation with (intra-amniotic infection and/or inflammation group, n=41) and without intra-amniotic infection and/or inflammation (non-intra-amniotic infection and/or inflammation, n=54). Controls (n=48) were outpatient pregnant women without preterm labor or preterm prelabor rupture of membranes. Intra-amniotic infection was defined by a positive amniotic fluid culture or positive 16S ribosomal RNA gene. Intra-amniotic inflammation was defined by using the amniotic fluid interleukin-6 cutoff levels previously reported by our group being >1.43 ng/mL in preterm prelabor rupture of membranes and >13.4 ng/mL in preterm labor. Fetal cardiac morphology and function was evaluated using echocardiography, and troponin-I and N-terminal pro-brain natriuretic peptide concentrations were measured in amniotic fluid from women with preterm labor or preterm prelabor rupture of membranes and compared with 20 amniotic fluid Biobank samples obtained for reasons other than preterm labor or preterm prelabor rupture of membranes or cardiac pathology. The data were adjusted for the estimated fetal weight below the 10th percentile and for preterm prelabor rupture of membranes at admission and also for gestational age at amniocentesis when amniotic fluid biomarkers were compared.

RESULTS

From 2018 to 2021, 143 fetuses were included; 95 fetuses were from mothers admitted with a diagnosis of preterm labor or preterm prelabor rupture of membranes, and among those, 41 (28.7%) were in the intra-amniotic infection and/or inflammation group and 54 (37.8%) were in the non-intra-amniotic infection and/or inflammation group. A total of 48 (33.6%) fetuses were included in the control group. Fetuses with preterm labor and/or preterm prelabor rupture of membranes had signs of subclinical cardiac concentric hypertrophy (median left wall thickness of 0.93 [interquartile range, 0.72-1.16] in the intra-amniotic infection and/or inflammation group; 0.79 [0.66-0.92] in the non-intra-amniotic infection and/or inflammation group; and 0.69 [0.56-0.83] in controls; P<.001) and diastolic dysfunction (tricuspid A duration 0.23 seconds [0.21-0.25], 0.24 [0.22-0.25], and 0.21 [0.2-0.23]; P=.007). Systolic function was similar among groups. Higher values of amniotic fluid troponin I (1413 pg/mL [927-2334], 1190 [829-1636], and 841 [671-959]; P<.001) and N-terminal pro-brain natriuretic peptide were detected (35.0%, 17%, and 0%; P=.005) in fetuses with preterm labor or preterm prelabor rupture of membranes when compared with the control group. The highest N-terminal pro-brain natriuretic peptide concentrations were found in the intra-amniotic infection and/or inflammation group.

CONCLUSION

Fetuses with preterm labor or preterm prelabor rupture of membranes showed signs of cardiac remodeling and subclinical dysfunction, which were more pronounced in those exposed to intra-amniotic infection and/or inflammation. These findings support that the cardiovascular effects observed in children and adults born preterm have, at least in part, a prenatal origin.

Antibiotic administration reduced intra-amniotic inflammation 7 days after preterm premature rupture of the membranes with intra-amniotic infection

OBJECTIVE

Intra-amniotic infections increase the risk of preterm delivery and short- and long-term fetal morbidity; however, no consensus exists on the choice of antimicrobial agents as treatment for these infections. We aimed to examine the efficacy of intravenous administration of sulbactam/ampicillin (SBT/ABPC) and azithromycin (AZM) for intra-amniotic infection in patients with preterm premature rupture of membranes (PPROM).

METHODS

This study followed a single-centered retrospective cohort design. We compared changes in interleukin 6 (IL-6) levels and the load of Ureaplasma species DNA in the amniotic fluid between singleton pregnancy patients with intra-amniotic infection (Group A) and without either intra-amniotic inflammation (IAI) or microbial invasion of the amniotic cavity (MIAC) (Group B) who developed PPROM between week 22, day 0 and week 33, day 6 of gestation and maintained pregnancy for ≥7 d after diagnosis (August 2014 to April 2020). Patients in Group A were treated with SBT/ABPC and AZM, whereas those in Group B were treated with ABPC and AZM or clarithromycin.

RESULTS

Thirty-one patients with IAI and 48 patients without either IAI or MIAC at diagnosis of PPROM underwent pregnancy/delivery management at our hospital. Following the study population selection, we evaluated six patients in Group A and 13 patients in Group B. Amniotic fluid IL-6 concentrations at the initial amniocentesis were high, ranging from 11.7 ng/mL to 139.2 ng/mL, indicating a state of severe IAI in all six patients in Group A. In five of the six patients in Group A, the amniotic fluid cultures during the first amniocentesis included Ureaplasma species only. In both groups, the amniotic fluid IL-6 concentration at the follow-up amniocentesis was lower than that at the initial amniocentesis (Group A: follow-up median 3.06 ng/mL [quartiles, 1.75-6.74], initial median 30.53 ng/mL [quartiles, 15.60-67.07], p＝.03; Group B: follow-up median 0.40 ng/mL [quartiles, 0.18-0.69], initial median 0.96 ng/mL [quartiles, 0.65-1.42], p＝.005); Group A showed a greater decrease than Group B (p < .001). No difference was found between the microbial loads of Ureaplasma species DNA in the initial and follow-up amniocentesis (p = .13).

CONCLUSIONS

In patients with PPROM and intra-amniotic infection, IL-6 levels in the amniotic fluid decreased significantly from before antimicrobial administration to day 7. This decrease is thought to be mainly due to the effects of intravenous AZM. The efficacy of AZM in patients with PPROM needs to be further confirmed via randomized controlled studies in the future.

Amniotic fluid CD36 in pregnancies complicated by spontaneous preterm delivery: a retrospective cohort study

OBJECTIVE

The aim of this study was to evaluate CD36 concentrations in amniotic fluid in pregnancies complicated by spontaneous delivery with intact fetal membranes (preterm labor, PTL) and preterm prelabor rupture of membranes (PPROM) with respect to the presence of the intra-amniotic infection.

METHODS

A total of 80 women with PPROM and 71 with PTL were included in the study. Amniotic fluid samples were obtained by transabdominal amniocentesis. Amniotic fluid CD36 concentrations were assessed by enzyme-linked immunosorbent assay. Microbial colonization of the amniotic cavity (MIAC) was determined by the cultivation and non-cultivation approach. Intra-amniotic inflammation (IAI) was defined as an amniotic fluid bedside interleukin-6 concentration ≥3000 pg/mL. Intra-amniotic infection was characterized by the presence of both MIAC and IAI.

RESULTS

Women with PPROM with intra-amniotic infection had higher amniotic fluid CD36 concentrations than women without infection (with infection: median 346 pg/mL, IQR 262-384 vs. without infection: median 242 pg/mL, IQR 199-304; p = .006) A positive correlation between amniotic fluid CD36 concentrations and interleukin-6 concentrations was found (rho = 0.48; p < .0001). In PTL pregnancies, no statistically significant difference was found in the amniotic fluid level of CD36 between intra-amniotic infection, sterile IAI, and negative amniotic fluid.

CONCLUSIONS

The presence of intra-amniotic infection is characterized by higher amniotic fluid CD36 concentrations in pregnancies complicated by PPROM. An amniotic fluid CD36 cutoff value of 252.5 pg/mL was found to be optimal for the prediction of intra-amniotic infection. In PTL pregnancies, no statistically significant change in CD36 concentration was found with respect to the presence of intra-amniotic infection.

Amniotic fluid sludge is associated with earlier preterm delivery and raised cervicovaginal interleukin 8 concentrations

BACKGROUND

Preterm birth is the leading cause of global neonatal mortality. Amniotic fluid sludge, thought to indicate intra-amniotic infection, may have potential as a clinical biomarker of preterm birth risk.

OBJECTIVE

This study aimed to analyze whether the presence of amniotic fluid sludge in pregnant participants with a known short cervical length can help improve the understanding of the etiology and guide management choice.

STUDY DESIGN

This was a retrospective cohort study analyzing the effects of amniotic fluid sludge presence on the risk of preterm birth in high-risk asymptomatic pregnant participants with a short cervical length (<25 mm) at a large tertiary referral maternity center in London. Amniotic fluid sludge was detected on a routine transvaginal ultrasound scan.

RESULTS

Overall, 147 pregnant participants with a short cervical length were identified, 54 of whom had amniotic fluid sludge. Compared with pregnant participants without amniotic fluid sludge, pregnant participants with amniotic fluid sludge were more likely to have a short cervical length (19 vs 14 mm, respectively; P<.0001) and increased cervicovaginal fetal fibronectin concentrations at diagnosis (125 vs 45 ng/mL, respectively; P=.0006). Pregnant participants with amniotic fluid sludge were at increased risk of midtrimester loss and delivery before 24 weeks of gestation (relative risk, 3.4; 95% confidence interval, 1.2-10.3). Furthermore, this study showed that pregnant participants with amniotic fluid sludge have increased cervicovaginal interleukin 8 concentrations, supporting the concept of amniotic fluid sludge as an indicator of an inflammatory response to microbial invasion (P=.03). Neonatal outcomes were similar between the 2 groups.

CONCLUSION

In our cohort of high-risk asymptomatic pregnant participants with a short cervical length, the presence of amniotic fluid sludge is associated with an increased risk of delivery before 24 weeks of gestation. Moreover, pregnant participants with amniotic fluid sludge were more likely to have raised fetal fibronectin levels and inflammatory cytokines, particularly interleukin 8, in the cervicovaginal fluid, supporting the concept that amniotic fluid sludge is associated with an infective or inflammatory process. Future research should aim to further establish the clinical significance of amniotic fluid sludge presence and guide subsequent management.

Association between intracervical Foley balloon and clinical chorioamnionitis among patients with group B streptococcus colonization undergoing induction with standardized labor management

BACKGROUND

Intracervical Foley balloons are commonly used for cervical ripening, but there has been a historical concern regarding an increased risk of clinical chorioamnionitis with Foley balloon use in patients with group B streptococcus.

OBJECTIVE

This study aimed to determine whether intracervical Foley balloon use in patients with group B streptococcus is associated with an increased risk of clinical chorioamnionitis.

STUDY DESIGN

This was a secondary analysis of a randomized controlled trial Mechanical and Pharmacologic Methods of Labor Induction: A Randomized Controlled Trial that compared cervical ripening agents within a standardized labor protocol. Foley balloon (alone, with oxytocin, or with misoprostol) was compared with misoprostol only to evaluate the primary outcome of clinical chorioamnionitis, defined based on the American College of Obstetricians and Gynecologists guidelines. Patients with a term, singleton pregnancy with intact membranes and an unfavorable cervix (Bishop score of ≤6 and dilation ≤2 cm) and a known group B streptococcus status were included. The secondary outcomes included a composite postpartum maternal infectious outcome consisting of any occurrence of endometritis, wound infection, postpartum urinary tract infection, or maternal sepsis; additional secondary outcomes included neonatal outcomes. Binomial regression with robust error variance was used to evaluate whether group B streptococcus status modified the relationship between Foley balloon use and clinical chorioamnionitis and to adjust for confounders.

RESULTS

A total of 491 patients were enrolled in the original trial. Of these patients, 467 had a known group B streptococcus status and underwent cervical ripening: 182 (39.0%) had group B streptococcus, and 285 (61.0%) did not have group B streptococcus. Moreover, 73.0% of patients received a Foley balloon, and 27.0% of patients did not receive a Foley balloon. There was no difference in the demographic or clinical characteristics between groups. The overall rate of clinical chorioamnionitis was 12.2%, with no difference between those with and without a Foley balloon (12.6% vs 11.1%, respectively; P=.66). Group B streptococcus status did not modify the association between Foley balloon use and clinical chorioamnionitis (relative risk, 0.93; 95% confidence interval, 0.50-1.72). This remained unchanged after adjusting for gestational age (adjusted relative risk, 0.87; 95% confidence interval, 0.45-1.67). Furthermore, other maternal and neonatal outcomes were similar between groups.

CONCLUSION

In this secondary analysis of a large randomized trial using a standardized labor protocol, there was no increased risk of infectious morbidity with Foley balloon use in patients overall and in patients with group B streptococcus. Our findings support that a Foley balloon can be safely used for cervical ripening in patients with group B streptococcus colonization.

Validation of diagnosis codes for chorioamnionitis in medical encounter data, 2013-2018

PURPOSE

Chorioamnionitis refers to intrauterine infection/inflammation that can be diagnosed clinically or from laboratory testing. This study aimed to validate chorioamnionitis International Classification of Diseases (ICD) codes using reference standards for clinical and histologic cases.

METHODS

Department of Defense Birth and Infant Health Research program data identified a cohort of live deliveries at two United States military hospitals from 2013 to 2018. Deliveries were screened for chorioamnionitis using ICD codes from maternal delivery records; a sample of screen positive and negative deliveries was selected for chart review. Primary analyses validated deliveries using a reference standard for clinical chorioamnionitis; secondary analyses employed a reference standard that also included histologic cases, but were limited by temporal differences in availability of laboratory data. Sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values were calculated with 95% confidence intervals (CIs).

RESULTS

Overall, 1857 deliveries (465 screen positive, 1392 screen negative) were eligible for analysis and 336 met the reference standard for clinical chorioamnionitis, yielding a PPV of 0.68 (95% CI 0.63, 0.72) and sensitivity of 0.76 (95% CI 0.72, 0.81). In secondary analyses, 390 deliveries met the reference standard for clinical or histologic chorioamnionitis, resulting in an overall PPV of 0.75 (95% CI 0.71, 0.79); in 2018, when more laboratory results were available, the PPV was 0.91 (95% CI 0.84, 0.97). NPV and specificity were ≥0.97 across reference standards.

CONCLUSIONS

Chorioamnionitis ICD codes exhibited moderate correlation with clinical disease, suggesting challenges in using medical encounter data to isolate clinical cases from those only identified through laboratory testing.

Validating the performance of 3 sepsis screening tools in patients with clinical chorioamnionitis

BACKGROUND

Maternal sepsis is a leading cause of maternal death in the United States. Approximately two-thirds of maternal deaths because of sepsis are related to delayed recognition or treatment. New early warning systems using a 2-step approach have been developed for the early recognition of sepsis in obstetrics; however, their performance has not been validated.

OBJECTIVE

This study aimed to assess the performance of 3 primary screening tools introduced by the Society of Obstetric Medicine Australia and New Zealand and the California Maternal Quality Care Collaborative for use in the first step of their 2-step early warning systems. The obstetrically modified quick Sequential (sepsis-related) Organ Failure Assessment score tool, the obstetrically modified Systemic Inflammatory Response Syndrome tool, and the obstetrically modified Systemic Inflammatory Response Syndrome 1 tool were evaluated for the early detection of sepsis in patients with clinically diagnosed chorioamnionitis.

STUDY DESIGN

This was a retrospective cohort study using prospectively collected clinical data at a tertiary care center and an affiliated healthcare system. The electronic health records were searched to identify and verify cases with clinically diagnosed chorioamnionitis between November 2017 and September 2022. The flow sheet for every patient was reviewed to determine when criteria were met for any of the 3 tools. The performance of these tools was analyzed using their sensitivity, specificity, positive and negative predictive values, and receiver operating characteristic curve for the identification of sepsis.

RESULTS

There were 545 cases that had the requisite data for inclusion in the analysis. Of note, 11 patients met the criteria for sepsis. Both the obstetrically modified Systemic Inflammatory Response Syndrome and obstetrically modified Systemic Inflammatory Response Syndrome 1 tools had overall similar test characteristics, which were notably different from the obstetrically modified quick Sequential Organ Failure Assessment tool. The screen-positive rate of the obstetrically modified quick Sequential Organ Failure Assessment tool (1.5%; 95% confidence interval, 0.6%-2.9%) was lower than that of the obstetrically modified Systemic Inflammatory Response Syndrome tool (60.0%; 95% confidence interval, 55.7%-64.1%) and the obstetrically modified Systemic Inflammatory Response Syndrome 1 tool (50.0%; 95% confidence interval, 45.8%-54.3%). The sensitivities of the obstetrically modified Systemic Inflammatory Response Syndrome tool (100.0%; 95% confidence interval, 71.5%-100.0%) and the obstetrically modified Systemic Inflammatory Response Syndrome 1 tool (100.0%; 95% confidence interval, 71.5%-100.0%) were higher than that of the obstetrically modified quick Sequential Organ Failure Assessment tool (18.0%; 95% confidence interval, 2.3%-51.8%). All 3 tools had high negative predictive values; however, their positive predictive values were poor.

CONCLUSION

This study demonstrated that all 3 tools had limitations in screening for sepsis among patients with a clinical diagnosis of chorioamnionitis. The obstetrically modified quick Sequential Organ Failure Assessment tool missed more than half of the sepsis cases and, thus, had poor performance as a primary screening tool for sepsis. Both the obstetrically modified Systemic Inflammatory Response Syndrome and obstetrically modified Systemic Inflammatory Response Syndrome 1 tools captured all sepsis cases; however, they tended to overdetect sepsis.

Impact of antimicrobial stewardship interventions on peripartum antibiotic prescribing in patients with penicillin allergy

BACKGROUND

Beta-lactam antibiotics (eg, penicillins, cephalosporins, and carbapenems) are preferred for group B streptococcus prophylaxis, intra-amniotic infection, and cesarean surgical site infection prophylaxis. Non-beta-lactam alternatives are associated with inferior efficacy and contribute to higher rates of surgical site infection and longer lengths of stay. Most patients who report a penicillin allergy can tolerate penicillins without any adverse reaction. There are low rates of cross-reactivity between penicillins and other beta-lactams, including cephalosporins and carbapenems. Efforts to evaluate penicillin allergy and promote the use of beta-lactams are needed.

OBJECTIVE

This study aimed to evaluate whether an antimicrobial stewardship intervention improved the use of first-line antibiotics for peripartum indications in patients with a reported penicillin allergy, following updates to institutional guidelines.

STUDY DESIGN

This was a retrospective study of adult patients presenting for vaginal or cesarean delivery at 2 hospitals within a healthcare system. Patients received at least 1 dose of antibiotics for a peripartum indication between May 1, 2018, and October 31, 2018 (preintervention group) and May 1, 2020, to October 31, 2020 (postintervention group). The stewardship intervention bundle, which was implemented between March 2019 and April 2020, included updates to institutional antibiotic guidelines, reclassification of severe penicillin allergy, development of obstetrical prophylaxis and treatment order sets, promotion of allergy referral services, and establishment of a physician champion. The primary outcome was the composite rates of patients with reported penicillin allergy who received a preferred antibiotic for a peripartum indication. The secondary measures included maternal and neonatal outcomes.

RESULTS

A total of 192 patients with a history of documented penicillin allergy were evaluated (96 patients in the preintervention group and 96 patients in the postintervention group). Hives were the most commonly reported index symptom in both groups (40/96 [41.7%] vs 39/96 [40.6%]; P=.883). After stewardship interventions, there was a significant increase in the rate of preferred antibiotic use (33/96 [34.3%] vs 81/96 [84.3%]; P<.001). The effect was the greatest in patients with nonsevere allergy (14/76 [18.4%] vs 68/82 [82.9%]; P<.001). There was no difference in the rates of postpartum endometritis, 30-day readmission, 90-day surgical site infection, or neonatal early-onset sepsis between the pre- and postintervention groups. Of note, 1 patient in the postintervention group experienced itching, and another patient developed a rash, both of which resolved with medical management.

CONCLUSION

A comprehensive antibiotic stewardship intervention was associated with a 50% increase in the use of preferred antibiotics for peripartum indications in patients with penicillin allergy. Allergic reactions with first-line beta-lactams were minimal and manageable.

Intra-Amniotic Inflammation or Infection: Suspected and Confirmed Diagnosis of "Triple I" at Term

Chorioamnionitis (CA) at term of pregnancy can have an infectious and/or inflammatory origin and is associated with adverse outcomes. Triple I (intrauterine inflammation, infection, or both, TI) has been proposed to reduce the overdiagnosis of infection and neonatal overtreatment. The aim of this study is to identify clinical and histological variables that could predict adverse outcomes when TI is suspected and/or confirmed. This retrospective cohort study included 404 pregnancies (gestational age ≥ 37 weeks) that were divided into 5 all-inclusive and mutually exclusive groups. TI was defined according to the NICHD definition of 2015, and it could be confirmed (TI+) or not confirmed (TI-) via histological examination. Signs of infection/inflammation that did not conform to the definition of TI were classified as "clinical suspicion" and could be supported (CS+) or not supported (CS-) by histology. Cases of histological chorioamnionitis (HCA) without clinical manifestation represented a fifth group. Whole placental involvement (WPLI) was defined as a histological inflammation involving the maternal and fetal sides. There were 113 TI+, 30 TI-, 186 CS+, 35 CS-, and 40 isolated HCA cases. WPLI was diagnosed in 133 cases (39.2%). Composite neonatal outcome (CNO) occurred in 114 cases (28.2%) while composite maternal outcome (CMO) occurred in 192 cases (47.5%). Compared with CS+, TI+ was more predictive of CNO (p = 0.001), CMO (p < 0.001), and WPLI (p = 0.005). WPLI was related both to CNO (p < 0.001) and to CMO (p = 0.046). TI+ and WPLI showed similar sensitivity but different specificity in predicting CNO. At logistic regression, CNO was independently predicted by TI+ (OR 2.21; p = 0.001) and by WPLI (OR 2.23; p = 0.001). Compared with CS, TI is a better predictor of CNO and can be useful for the identification of newborns at risk.

Evaluation of a clinical protocol for the management of fever in labor among pregnant women at term: A quality-improvement study

OBJECTIVE

To assess the impact of a quality-improvement initiative designed to increase diagnostic accuracy and adequate management of clinical chorioamnionitis (CC) at a tertiary center. Chorioamnionitis occurs in 1%-13% of term pregnancies and increases maternal and neonatal peripartum complications; often over-diagnosed, it leads to unnecessary investigations and treatments.

METHODS

This was an interrupted time-series study. In September 2017 two interventions were implemented: (1) staff training and (2) standardized clinical protocol for the management of fever in labor. All singleton term pregnancies were included. CC cases were reviewed in the pre-intervention (2015-2016, n = 179) and post-intervention (2017-2018, n = 142) groups. CC criteria based on the American College of Obstetricians and Gynecologists guidelines, antibiotics, maternal and neonatal outcomes, and pathology were compared. A cost-consequence analysis was performed.

RESULTS

Incidence of CC decreased from 8.2 to 5.6 per 10 person-year (P < 0.001). This was associated with a significant increase in diagnostic accuracy from 15.7% to 73.2% (P < 0.001). Weight-adjusted tobramycin dosage improved from 8.8% to 69.1% (P < 0.001). Maternal length of hospitalization and readmissions decreased significantly, without affecting neonatal sepsis rate. Interventions decreased yearly hospital costs associated with CC by 23.4%.

CONCLUSION

Standardizing the management of fever in labor significantly increased the diagnostic accuracy of CC and decreased the misuse of antibiotics in term pregnancies. CC costs decreased by 23.4%.

Reference values for interleukin-6 in the amniotic fluid of asymptomatic pregnant women

INTRODUCTION

Nowadays, proinflammatory factors are considered to play an important role in the pathophysiology of threatened preterm labor or chorioamnionitis. The aim of this study was to establish the normal reference range for interleukin-6 (IL-6) levels in the amniotic fluid and to identify factors which may alter this value.

MATERIAL AND METHODS

Prospective study in a tertiary-level center including asymptomatic pregnant women undergoing amniocentesis for genetic studies from October 2016 to September 2019. IL-6 measurements in amniotic fluid were performed using a fluorescence immunoassay with microfluidic technology (ELLA Proteinsimple, Bio Techne). Maternal history and pregnancy data were also recorded.

RESULTS

This study included 140 pregnant women. Of those, women who underwent termination of pregnancy were excluded. Therefore, a total of 98 pregnancies were included in the final statistical analysis. The mean gestational age was 21.86 weeks (range: 15-38.7) at the time of amniocentesis, and 38.6 weeks (range: 30.9-41.4) at delivery. No cases of chorioamnionitis were reported. The log₁₀ IL-6 values follow a normal distribution (W = 0.990, p = 0.692). The median, and the 5th, 10th, 90th, and 95th percentiles for IL-6 levels were 573, 105, 130, 1645, and 2260 pg/mL, respectively. The log₁₀ IL-6 values were not affected by gestational age (p = 0.395), maternal age (p = 0.376), body mass index (p = 0.551), ethnicity (p = 0.467), smoking status (p = 0.933), parity (p = 0.557), method of conception (p = 0.322), or diabetes mellitus (p = 0.381).

CONCLUSIONS

The log₁₀ IL-6 values follow a normal distribution. IL-6 values are independent of gestational age, maternal age, body mass index, ethnicity, smoking status, parity and method of conception. Our study provides a normal reference range for IL-6 levels in the amniotic fluid that can be used in future studies. We also observed that normal IL-6 values were higher in the amniotic fluid than in serum.

Changing Laboratory Practice for Early Detection of a Fetal Inflammatory Response: A Contemporary Approach

Neonates born with the fetal inflammatory response (FIR) are at risk of complications such as early-onset neonatal sepsis, meningitis, and pneumonia. Providing an early histopathological diagnosis of FIR is important to guide management but can be a challenge in busy laboratories. This is a retrospective cross-sectional study over a four-month duration recruiting all placental cases with histological chorioamnionitis in our institution. The diagnostic performance of the umbilical cord (UC) section in identifying FIR, relative to the corresponding subsequent placental sections, was assessed. Clinical predictors of umbilical cord FIR were also investigated. A total of 390 UC sections were analyzed, of which 206 (52.8%) were found positive for FIR: 111 cases (53.9%) stage 1, 87 (42.2%) stage 2, and 8 (3.9%) stage 3. Our data revealed a good diagnostic sensitivity, specificity, positive predictive value, and accuracy of 76.2% (95%CI: 68.6-82.7%), 82.4% (95%CI: 65.5-93.2%), 95.0% (95%CI: 90.2-97.6%), and 77.3% (95%CI: 70.6-83.1%) respectively, in cases when clinical chorioamnionitis, fever and/or prolonged rupture of membrane (PROM) were suspected, with the area under the curve of 0.793. A maternal inflammatory response (MIR) was correlated with FIR (p < 0.001). Multivariate logistic regression analysis indicated that the higher the gestational age, clinical suspicion of chorioamnionitis, fever, and/or PROM, and the higher the stage of MIR significantly increased the odds of FIR (p < 0.001). UC section diagnosis of FIR is reasonably accurate in cases with clinical chorioamnionitis, fever, and/or PROM. Changing current laboratory practice to rapid processing of UC ahead of the rest of the other placental sections can be recommended in busy pathology departments.

Noninvasive prediction models of intra-amniotic infection in women with preterm labor

BACKGROUND

Among women with preterm labor, those with intra-amniotic infection present the highest risk of early delivery and the most adverse outcomes. The identification of intra-amniotic infection requires amniocentesis, perceived as too invasive by women and physicians. Noninvasive methods for identifying intra-amniotic infection and/or early delivery are crucial to focus early efforts on high-risk preterm labor women while avoiding unnecessary interventions in low-risk preterm labor women.

OBJECTIVE

This study modeled the best performing models, integrating biochemical data with clinical and ultrasound information to predict a composite outcome of intra-amniotic infection and/or spontaneous delivery within 7 days.

STUDY DESIGN

From 2015 to 2020, data from a cohort of women, who underwent amniocentesis to rule in or rule out intra-amniotic infection or inflammation, admitted with a diagnosis of preterm labor at <34 weeks of gestation at the Hospital Clinic and Hospital Sant Joan de Déu, Barcelona, Spain, were used. At admission, transvaginal ultrasound was performed, and maternal blood and vaginal samples were collected. Using high-dimensional biology, vaginal proteins (using multiplex immunoassay), amino acids (using high-performance liquid chromatography), and bacteria (using 16S ribosomal RNA gene amplicon sequencing) were explored to predict the composite outcome. We selected ultrasound, maternal blood, and vaginal predictors that could be tested with rapid diagnostic techniques and developed prediction models employing machine learning that was applied in a validation cohort.

RESULTS

A cohort of 288 women with preterm labor at <34 weeks of gestation, of which 103 (35%) had a composite outcome of intra-amniotic infection and/or spontaneous delivery within 7 days, were included in this study. The sample was divided into derivation (n=116) and validation (n=172) cohorts. Of note, 4 prediction models were proposed, including ultrasound transvaginal cervical length, maternal C-reactive protein, vaginal interleukin 6 (using an automated immunoanalyzer), vaginal pH (using a pH meter), vaginal lactic acid (using a reflectometer), and vaginal Lactobacillus genus (using quantitative polymerase chain reaction), with areas under the receiving operating characteristic curve ranging from 82.2% (95% confidence interval, ±3.1%) to 85.2% (95% confidence interval, ±3.1%), sensitivities ranging from 76.1% to 85.9%, and specificities ranging from 75.2% to 85.1%.

CONCLUSION

The study results have provided proof of principle of how noninvasive methods suitable for point-of-care systems can select high-risk cases among women with preterm labor and might substantially aid in clinical management and outcomes while improving the use of resources and patient experience.

Characterization of amniotic fluid sludge in preterm and term gestations

OBJECTIVE

To describe the characteristics of amniotic fluid sludge obtained from patients in term and preterm gestations.

METHODS

This cross-sectional study included patients with dense aggregates of particulate matter detected in amniotic fluid, observed with transvaginal sonography. All patients were in labor and had an impending delivery, either preterm or at term. Echogenic material contained within amniotic fluid was retrieved transvaginally by needle amniotomy under direct visualization. The amniotic fluid analysis consisted of a Gram stain, cultures for aerobic/anaerobic bacteria and genital mycoplasmas, and a white blood cell count.

RESULTS

Twenty-five patients ranging from 18 to 41 weeks of gestation were included in the study. We observed the following: (1) the appearance of amniotic fluid was consistent with pus-like material, vernix, or meconium by naked eye examination; (2) samples collected before 33 weeks of gestation (n = 13) had a pus-like appearance; however, after this gestational age, most of the samples [83% (10/12)] appeared to be consistent with vernix; (3) amniotic fluid cultures were positive for microorganisms in 13 patients, of which 10 were preterm gestations before 33 weeks; (4) the most frequent microorganisms retrieved by culture were genital mycoplasmas (Ureaplasma urealyticum [46% (6/13)]), followed by Mycoplasma hominis [31% (4/13)] and Candida albicans [15% (2/13)]; and (5) patients with sonographic particulate matter in preterm gestations frequently presented acute histologic chorioamnionitis and funisitis, but these conditions were rare in patients at term.

CONCLUSION

The nature of amniotic fluid particulate material varies as a function of gestational age. The material obtained in preterm gestations is frequently related to an inflammatory process, while that obtained at term is often consistent with vernix and appears to represent a maturational process.

Cervical insufficiency, amniotic fluid sludge, intra-amniotic infection, and maternal bacteremia: the need for a point-of-care test to assess inflammation and bacteria in amniotic fluid

Acute cervical insufficiency is frequently associated with subclinical intra-amniotic inflammation and intra-amniotic infection. Amniotic fluid analysis has been recommended prior to the placement of a cervical cerclage given that preexisting infection is associated with adverse pregnancy outcome. We report a case for which commonly available laboratory tests-amniotic fluid Gram stain, white blood cell count, and glucose concentration-did not detect either intra-amniotic inflammation, diagnosed by elevated amniotic fluid interleukin-6, or intra-amniotic infection, diagnosed by cultivation. Following cerclage placement, the patient developed clinical chorioamnionitis and bacteremia and experienced a spontaneous mid-trimester pregnancy loss. This case illustrates the need for a rapid and sensitive point-of-care test capable of detecting infection or inflammation, given recent evidence in support of treatment of intra-amniotic infection and intra-amniotic inflammation with antimicrobial agents.

Effect of gestational age at first delivery and interpregnancy interval on the recurrence of clinical chorioamnionitis

BACKGROUND

There is an increased odds of having a recurrence of clinical chorioamnionitis in patients with a diagnosis of clinical chorioamnionitis compared with those without clinical chorioamnionitis in a previous pregnancy. However, it is unclear how gestational age at delivery of the first pregnancy or interpregnancy interval may contribute to this increased risk.

OBJECTIVE

This study aimed to evaluate how gestational age of delivery in a first pregnancy and interpregnancy interval affect the odds of recurrent clinical chorioamnionitis.

STUDY DESIGN

Using maternally linked birth record files, Nulliparous patients from California with at least 2 consecutive deliveries between the gestational ages of 20 and 44 weeks from 2007 to 2012 were identified. The rates of clinical chorioamnionitis in the second pregnancy for patients with clinical chorioamnionitis vs those without clinical chorioamnionitis in the first pregnancy, stratified by the gestational age at delivery of the first pregnancy were determined. As a secondary analysis, the analysis by interpregnancy interval (<18 months vs ≥18 months) was stratified. Corresponding crude and adjusted odds ratios for each stratum were calculated to assess the association of clinical chorioamnionitis in the first and second pregnancies.

RESULTS

Among 31,571 nulliparous patients with clinical chorioamnionitis in the first pregnancy, the frequency of clinical chorioamnionitis in the next pregnancy was 4.0% (1257 cases). This was in comparison with the 1.0% (9177 of 896,154) of nulliparous patients without clinical chorioamnionitis in the first pregnancy who were diagnosed with clinical chorioamnionitis in the next pregnancy (adjusted odds ratio, 2.78; 95% confidence interval, 2.61-2.96). The absolute frequency of recurrence was the highest (54 cases [8.2%]) in those who delivered at 20 to 24 weeks of gestation in the first pregnancy with the diagnosis of clinical chorioamnionitis (adjusted odds ratio, 1.76; 95% confidence interval, 1.25-2.48). For pregnancies delivered at term in the first pregnancy, the frequency of clinical chorioamnionitis in the next pregnancy was higher in those diagnosed with clinical chorioamnionitis in the first pregnancy than in those without clinical chorioamnionitis in the first pregnancy (4.0% vs 1.0%; adjusted odds ratio, 2.85; 95% confidence interval, 2.66-3.05). An interpregnancy interval of <18 months was not associated with increased odds of recurrent clinical chorioamnionitis.

CONCLUSION

The odds of recurrence of clinical chorioamnionitis were the strongest when a patient delivered in the term to postterm period in the first pregnancy, with the absolute risk being the highest when the first pregnancy was delivered in the periviable period (20-24 weeks of gestation). The interpregnancy interval did not seem to modify the risk of recurrent clinical chorioamnionitis.

Individualized treatment of preterm premature rupture of membranes to prolong the latency period, reduce the rate of preterm birth, and improve neonatal outcomes

BACKGROUND

Preterm premature rupture of membranes complicates approximately 3% of pregnancies. Currently, in the absence of chorioamnionitis or placental abruption, expectant management, including antenatal steroids for lung maturation and prophylactic antibiotic treatment, is recommended. The benefits of individualized management have not been adequately explored.

OBJECTIVE

This study aimed to compare the impact of 2 different management strategies of preterm premature rupture of membranes in 2 tertiary obstetrical centers on latency of >7 days, latency to birth, chorioamnionitis, funisitis, and short-term adverse maternal and neonatal outcomes.

STUDY DESIGN

This was a multicenter retrospective study of women with singleton pregnancies with preterm premature rupture of membranes from 23 0/7 to 33 6/7 weeks of gestation between 2014 and 2018 and undelivered within 24 hours after hospital admission managed at Sunnybrook Health Sciences Center, Toronto, Canada (standard management group), and BCNatal (Hospital Clínic of Barcelona and Hospital Sant Joan de Déu Barcelona), Barcelona, Spain (individualized management group), following local protocols. The standard management group received similar management for all patients, which included a standard antibiotic regimen and routine maternal and fetal surveillance, whereas the individualized management group received personalized management on the basis of amniocentesis at hospital admission (if possible), to rule out microbial invasion of the amniotic cavity and targeted treatment. The exclusion criteria were cervical dilatation >2 cm, active labor, contraindications to expectant management (acute chorioamnionitis, placental abruption, or abnormal fetal tracing), and major fetal anomalies. The primary outcome was latency of >7 days, and the secondary outcomes included latency to birth, chorioamnionitis, and short-term adverse maternal and neonatal outcomes. Statistical comparisons between groups were conducted with propensity score weighting.

RESULTS

A total of 513 pregnancies with preterm premature rupture of membranes were included in this study: 324 patients received standard management, and 189 patients received individualized management, wherein amniocentesis was performed in 112 cases (59.3%). After propensity score weighting, patients receiving individualized management had a higher latency of >7 days (76.0% vs 41.6%; P<.001) and latency to birth (18.1±14.7 vs 9.7±9.7 days; P<.001). Although a higher rate of clinical chorioamnionitis was suspected in the individualized management group than the standard group (34.5% vs 22.0%; P<.01), there was no difference between the groups in terms of histologic chorioamnionitis (67.2% vs 73.4%; P=.16), funisitis (57.6% vs 58.1%; P=.92), or composite infectious maternal outcomes (9.1% vs 7.9%; P=.64). Prolonged latency in the individualized management group was associated with a significant reduction of preterm birth at <32 weeks of gestation (72.1% vs 90.5%; P<.001), neonatal intensive care unit admission (75.6% vs 83.0%; P=.046), and neonatal respiratory support at 28 days of life (16.1% vs 26.1%; P<.01) compared with that in the standard management group. Moreover, prolonged latency was not associated with neonatal severe morbidity at discharge (survival without severe morbidity, 80.4% vs 73.5%; P=.09).

CONCLUSION

Individualized management of preterm premature rupture of membranes may prolong pregnancy and reduce preterm birth at <32 weeks of gestation, the need for neonatal support, and neonatal intensive care unit admissions, without an increase in histologic chorioamnionitis, funisitis, neonatal infection-related morbidity, and short-term adverse maternal and neonatal outcomes.

Does the Degree of Maternal Fever in the Setting of Chorioamnionitis Lead to Adverse Neonatal Outcomes?

Objective  The effect of the degree of maternal fever in the setting of chorioamnionitis on neonatal morbidity is unclear. The objective of this study is to assess the association between high maternal fevers (≥ 39°C) on neonatal morbidity. Study Design  Secondary analysis of Maternal-Fetal Medicine Units (MFMU) Cesarean Registry data obtained from 1999 to 2002 among singleton gestations with chorioamnionitis. Women with a temperature less than 39°C (low fever) compared with those with greater than or equal to 39°C (high fever). Primary outcome was a composite of adverse neonatal outcomes such as death, sepsis, necrotizing enterocolitis, grade-3 or -4 intraventricular hemorrhage, seizure within 24 hours of delivery, intubation within 24 hours of delivery, and requiring cardiopulmonary resuscitation. Demographic characteristics compared using Fisher's exact and Wilcoxon's rank-sum test as appropriate. Multivariate logistic regression analysis with performed to control for cofounders. Stratified analysis also performed to assess outcomes in term infants. Results  Of 1,313 included women, 1,200 (91.3%) were in the low fever group and 113 (8.7%) were in the high fever group. Women in the high fever group were more likely to be African American and group B Streptococcus positive. No difference in primary outcome was noted between the groups (38.9% high fever vs. 35.8% low fever, p  = 0.54). High maternal fever was associated with increased risk of NICU admission (48.1 vs. 50.4%, p  = 0.02). When controlling for African American race, preterm birth, and delivery route, patients with high fever were not more likely to have adverse neonatal outcomes (adjusted odds ratio [aOR] = 1.28, 95% confidence interval [CI]: 0.84, 1.98). In the analysis limited to term infants, when controlling for confounders, high fever, similarly, was not associated with increased odds of adverse neonatal outcomes (aOR = 1.59, 95% CI: 0.96, 2.65). Conclusion  The degree of maternal fever does not appear to be associated with an increased likelihood of adverse neonatal outcomes. Better understanding maternal factors that affect neonatal morbidity in the setting of chorioamnionitis is critical. Key Points High maternal fever in the setting of chorioamnionitis does not appear to have an increased likelihood of adverse neonatal outcomes.It is important to identify factors that may increase the risk of adverse outcomes such as early onset sepsis.Maternal fever may not be a strong indicator for neonatal outcomes and antibiotic protocols.

Bacteria in the amniotic fluid without inflammation: early colonization vs. contamination

OBJECTIVES

Intra-amniotic infection, defined by the presence of microorganisms in the amniotic cavity, is often accompanied by intra-amniotic inflammation. Occasionally, laboratories report the growth of bacteria or the presence of microbial nucleic acids in amniotic fluid in the absence of intra-amniotic inflammation. This study was conducted to determine the clinical significance of the presence of bacteria in amniotic fluid samples in the absence of intra-amniotic inflammation.

METHODS

A retrospective cross-sectional study included 360 patients with preterm labor and intact membranes who underwent transabdominal amniocentesis for evaluation of the microbial state of the amniotic cavity as well as intra-amniotic inflammation. Cultivation techniques were used to isolate microorganisms, and broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) was utilized to detect the nucleic acids of bacteria, viruses, and fungi.

RESULTS

Patients whose amniotic fluid samples evinced microorganisms but did not indicate inflammation had a similar perinatal outcome to those without microorganisms or inflammation [amniocentesis-to-delivery interval (p=0.31), spontaneous preterm birth before 34 weeks (p=0.83), acute placental inflammatory lesions (p=1), and composite neonatal morbidity (p=0.8)].

CONCLUSIONS

The isolation of microorganisms from a sample of amniotic fluid in the absence of intra-amniotic inflammation is indicative of a benign condition, which most likely represents contamination of the specimen during the collection procedure or laboratory processing rather than early colonization or infection.

High Mobility Group Box 1 in Pig Amniotic Membrane Experimentally Infected with E. coli O55

Intra-amniotic infections (IAI) are one of the reasons for preterm birth. High mobility group box 1 (HMGB1) is a nuclear protein with various physiological functions, including tissue healing. Its excessive extracellular release potentiates inflammatory reaction and can revert its action from beneficial to detrimental. We infected the amniotic fluid of a pig on the 80th day of gestation with 1 × 10⁴ colony forming units (CFUs) of E. coli O55 for 10 h, and evaluated the appearance of HMGB1, receptor for glycation endproducts (RAGE), and Toll-like receptor (TLR) 4 in the amniotic membrane and fluid. Sham-infected amniotic fluid served as a control. The expression and release of HMGB1 were evaluated by Real-Time PCR, immunofluorescence, immunohistochemistry, and ELISA. The infection downregulated HMGB1 mRNA expression in the amniotic membrane, changed the distribution of HMGB1 protein in the amniotic membrane, and increased its level in amniotic fluid. All RAGE mRNA, protein expression in the amniotic membrane, and soluble RAGE level in the amniotic fluid were downregulated. TLR4 mRNA and protein expression and soluble TLR4 were all upregulated. HMGB1 is a potential target for therapy to suppress the exaggerated inflammatory response. This controlled expression and release can, in some cases, prevent the preterm birth of vulnerable infants. Studies on suitable animal models can contribute to the development of appropriate therapy.

Amniotic fluid interleukin 6 and interleukin 8 are superior predictors of fetal lung injury compared with maternal or fetal plasma cytokines or placental histopathology in a nonhuman primate model

BACKGROUND

Intra-amniotic infection or inflammation is common in early preterm birth and associated with substantial neonatal lung morbidity owing to fetal exposure to proinflammatory cytokines and infectious organisms. Amniotic fluid interleukin 8, a proinflammatory cytokine, was previously correlated with the development of neonatal bronchopulmonary dysplasia, but whether amniotic fluid cytokines or placental pathology more accurately predicts neonatal lung pathology and morbidity is unknown. We have used a pregnant nonhuman primate model of group B Streptococcus infection to study the pathogenesis of intra-amniotic infection, bacterial invasion of the amniotic cavity and fetus, and microbial-host interactions. In this nonhuman primate model, we have studied the pathogenesis of group B Streptococcus strains with differing potential for virulence, which has resulted in a spectrum of intra-amniotic infection and fetal lung injury that affords the opportunity to study the inflammatory predictors of fetal lung pathology and injury.

OBJECTIVE

This study aimed to determine whether fetal lung injury is best predicted by placental histopathology or the cytokine response in amniotic fluid or maternal plasma.

STUDY DESIGN

Chronically catheterized pregnant monkeys (Macaca nemestrina, pigtail macaque) at 116 to 125 days gestation (term at 172 days) received a choriodecidual inoculation of saline (n=5), weakly hemolytic group B Streptococcus strain (n=5, low virulence), or hyperhemolytic group B Streptococcus strain (n=5, high virulence). Adverse pregnancy outcomes were defined as either preterm labor, microbial invasion of the amniotic cavity, or development of the fetal inflammatory response syndrome. Amniotic fluid and maternal and fetal plasma samples were collected after inoculation, and proinflammatory cytokines (tumor necrosis factor alpha, interleukin beta, interleukin 6, interleukin 8) were measured by a multiplex assay. Cesarean delivery was performed at the time of preterm labor or within 1 week of inoculation. Fetal necropsy was performed at the time of delivery. Placental pathology was scored in a blinded fashion by a pediatric pathologist, and fetal lung injury was determined by a semiquantitative score from histopathology evaluating inflammatory infiltrate, necrosis, tissue thickening, or collapse scored by a veterinary pathologist.

RESULTS

The principal findings in our study are as follows: (1) adverse pregnancy outcomes occurred more frequently in animals receiving hyperhemolytic group B Streptococcus (80% with preterm labor, 80% with fetal inflammatory response syndrome) than in animals receiving weakly hemolytic group B Streptococcus (40% with preterm labor, 20% with fetal inflammatory response syndrome) and in controls (0% preterm labor, 0% fetal inflammatory response syndrome); (2) despite differences in the rate of adverse pregnancy outcomes and fetal inflammatory response syndrome, fetal lung injury scores were similar between animals receiving the weakly hemolytic group B Streptococcus strains and animals receiving the hyperhemolytic group B Streptococcus strains; (3) fetal lung injury score was significantly correlated with peak amniotic fluid cytokines interleukin 6 and interleukin 8 but not tumor necrosis factor alpha or interleukin 1 beta; and (4) fetal lung scores were poorly correlated with maternal and fetal plasma cytokine levels and placental pathology.

CONCLUSION

Amniotic fluid interleukin 6 and interleukin 8 levels were superior predictors of fetal lung injury than placental histopathology or maternal plasma cytokines. This evidence supports a role for amniocentesis in the prediction of neonatal lung morbidity owing to intra-amniotic infection, which cannot be provided by cytokine analysis of maternal plasma or placental histopathology.

RNA Sequencing Reveals Distinct Immune Responses in the Chorioamniotic Membranes of Women with Preterm Labor and Microbial or Sterile Intra-amniotic Inflammation

Preterm labor precedes premature birth, the leading cause of neonatal morbidity and mortality worldwide. Preterm labor can occur in the context of either microbe-associated intra-amniotic inflammation (i.e., intra-amniotic infection) or intra-amniotic inflammation in the absence of detectable microorganisms (i.e., sterile intra-amniotic inflammation). Both intra-amniotic infection and sterile intra-amniotic inflammation trigger local immune responses that have deleterious effects on fetal life. Yet, the extent of such immune responses in the fetal tissues surrounding the amniotic cavity (i.e., the chorioamniotic membranes) is poorly understood. By using RNA sequencing (RNA seq) as a discovery approach, we found that there were significant transcriptomic differences involving host response to pathogens in the chorioamniotic membranes of women with intra-amniotic infection compared to those from women without inflammation. In addition, the sterile or microbial nature of intra-amniotic inflammation was associated with distinct transcriptomic profiles in the chorioamniotic membranes. Moreover, the immune response in the chorioamniotic membranes of women with sterile intra-amniotic inflammation was milder in nature than that induced by microbes and involved the upregulation of alarmins and inflammasome-related molecules. Lastly, the presence of maternal and fetal inflammatory responses in the placenta was associated with the upregulation of immune processes in the chorioamniotic membranes. Collectively, these findings provide insight into the immune responses against microbes or alarmins that take place in the fetal tissues surrounding the amniotic cavity, shedding light on the immunobiology of preterm labor and birth.

Clinical chorioamnionitis at term X: microbiology, clinical signs, placental pathology, and neonatal bacteremia - implications for clinical care

OBJECTIVES

Clinical chorioamnionitis at term is considered the most common infection-related diagnosis in labor and delivery units worldwide. The syndrome affects 5-12% of all term pregnancies and is a leading cause of maternal morbidity and mortality as well as neonatal death and sepsis. The objectives of this study were to determine the (1) amniotic fluid microbiology using cultivation and molecular microbiologic techniques; (2) diagnostic accuracy of the clinical criteria used to identify patients with intra-amniotic infection; (3) relationship between acute inflammatory lesions of the placenta (maternal and fetal inflammatory responses) and amniotic fluid microbiology and inflammatory markers; and (4) frequency of neonatal bacteremia.

METHODS

This retrospective cross-sectional study included 43 women with the diagnosis of clinical chorioamnionitis at term. The presence of microorganisms in the amniotic cavity was determined through the analysis of amniotic fluid samples by cultivation for aerobes, anaerobes, and genital mycoplasmas. A broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry was also used to detect bacteria, select viruses, and fungi. Intra-amniotic inflammation was defined as an elevated amniotic fluid interleukin-6 (IL-6) concentration ≥2.6 ng/mL.

RESULTS

(1) Intra-amniotic infection (defined as the combination of microorganisms detected in amniotic fluid and an elevated IL-6 concentration) was present in 63% (27/43) of cases; (2) the most common microorganisms found in the amniotic fluid samples were Ureaplasma species, followed by Gardnerella vaginalis; (3) sterile intra-amniotic inflammation (elevated IL-6 in amniotic fluid but without detectable microorganisms) was present in 5% (2/43) of cases; (4) 26% of patients with the diagnosis of clinical chorioamnionitis had no evidence of intra-amniotic infection or intra-amniotic inflammation; (5) intra-amniotic infection was more common when the membranes were ruptured than when they were intact (78% [21/27] vs. 38% [6/16]; p=0.01); (6) the traditional criteria for the diagnosis of clinical chorioamnionitis had poor diagnostic performance in identifying proven intra-amniotic infection (overall accuracy, 40-58%); (7) neonatal bacteremia was diagnosed in 4.9% (2/41) of cases; and (8) a fetal inflammatory response defined as the presence of severe acute funisitis was observed in 33% (9/27) of cases.

CONCLUSIONS

Clinical chorioamnionitis at term, a syndrome that can result from intra-amniotic infection, was diagnosed in approximately 63% of cases and sterile intra-amniotic inflammation in 5% of cases. However, a substantial number of patients had no evidence of intra-amniotic infection or intra-amniotic inflammation. Evidence of the fetal inflammatory response syndrome was frequently present, but microorganisms were detected in only 4.9% of cases based on cultures of aerobic and anaerobic bacteria in neonatal blood.

Intra-amniotic inflammation induces preterm birth by activating the NLRP3 inflammasome†

Intra-amniotic inflammation is strongly associated with spontaneous preterm labor and birth, the leading cause of perinatal mortality and morbidity worldwide. Previous studies have suggested a role for the NLRP3 (NLR family pyrin domain-containing protein 3) inflammasome in the mechanisms that lead to preterm labor and birth. However, a causal link between the NLRP3 inflammasome and preterm labor/birth induced by intra-amniotic inflammation has not been established. Herein, using an animal model of lipopolysaccharide-induced intra-amniotic inflammation (IAI), we demonstrated that there was priming of the NLRP3 inflammasome (1) at the transcriptional level, indicated by enhanced mRNA expression of inflammasome-related genes (Nlrp3, Casp1, Il1b); and (2) at the protein level, indicated by greater protein concentrations of NLRP3, in both the fetal membranes and decidua basalis prior to preterm birth. Additionally, we showed that there was canonical activation of the NLRP3 inflammasome in the fetal membranes, but not in the decidua basalis, prior to IAI-induced preterm birth as evidenced by increased protein levels of active caspase-1. Protein concentrations of released IL1β were also increased in both the fetal membranes and decidua basalis, as well as in the amniotic fluid, prior to IAI-induced preterm birth. Finally, using the specific NLRP3 inhibitor, MCC950, we showed that in vivo inhibition of the NLRP3 inflammasome reduced IAI-induced preterm birth and neonatal mortality. Collectively, these results provide a causal link between NLRP3 inflammasome activation and spontaneous preterm labor and birth in the context of intra-amniotic inflammation. We also showed that, by targeting the NLRP3 inflammasome, adverse pregnancy and neonatal outcomes can be significantly reduced.

Intra-Amniotic Infection with Ureaplasma parvum Causes Preterm Birth and Neonatal Mortality That Are Prevented by Treatment with Clarithromycin

Preterm birth is the leading cause of neonatal morbidity and mortality worldwide. Multiple etiologies are associated with preterm birth; however, 25% of preterm infants are born to a mother with intra-amniotic infection, most commonly due to invasion of the amniotic cavity by Ureaplasma species. Much research has focused on establishing a link between Ureaplasma species and adverse pregnancy/neonatal outcomes; however, little is known about the taxonomy of and host response against Ureaplasma species. Here, we applied a multifaceted approach, including human samples, in vivo models, and in vitro manipulations, to study the maternal-fetal immunobiology of Ureaplasma infection during pregnancy. Furthermore, we investigated the use of clarithromycin as a treatment for this infection. Our research provides translational knowledge that bolsters scientific understanding of Ureaplasma species as a cause of adverse pregnancy/neonatal outcomes and gives strong evidence for the use of clarithromycin as the recommended treatment for women intra-amniotically infected with Ureaplasma species.

Intra-amniotic infection is strongly associated with adverse pregnancy and neonatal outcomes. Most intra-amniotic infections are due to Ureaplasma species; however, the pathogenic potency of these genital mycoplasmas to induce preterm birth is still controversial. Here, we first laid out a taxonomic characterization of Ureaplasma isolates from women with intra-amniotic infection, which revealed that Ureaplasma parvum is the most common bacterium found in this clinical condition. Next, using animal models, we provided a causal link between intra-amniotic inoculation with Ureaplasma species and preterm birth. Importantly, the intra-amniotic inoculation of Ureaplasma species induced high rates of mortality in both preterm and term neonates. The in vivo potency of U. parvum to induce preterm birth was not associated with known virulence factors. However, term-derived and preterm-derived U. parvum isolates were capable of inducing an intra-amniotic inflammatory response. Both U. parvum isolates invaded several fetal tissues, primarily the fetal lung, and caused fetal inflammatory response syndrome. This bacterium was also detected in the placenta, reproductive tissues, and most severely in the fetal membranes, inducing a local inflammatory response that was replicated in an in vitro model. Importantly, treatment with clarithromycin, a recently recommended yet not widely utilized antibiotic, prevented the adverse pregnancy and neonatal outcomes induced by U. parvum. These findings shed light on the maternal-fetal immunobiology of intra-amniotic infection.

Chronic Intra-Uterine Ureaplasma parvum Infection Induces Injury of the Enteric Nervous System in Ovine Fetuses

Background: Chorioamnionitis, inflammation of the fetal membranes during pregnancy, is often caused by intra-amniotic (IA) infection with single or multiple microbes. Chorioamnionitis can be either acute or chronic and is associated with adverse postnatal outcomes of the intestine, including necrotizing enterocolitis (NEC). Neonates with NEC have structural and functional damage to the intestinal mucosa and the enteric nervous system (ENS), with loss of enteric neurons and glial cells. Yet, the impact of acute, chronic, or repetitive antenatal inflammatory stimuli on the development of the intestinal mucosa and ENS has not been studied. The aim of this study was therefore to investigate the effect of acute, chronic, and repetitive microbial exposure on the intestinal mucosa, submucosa and ENS in premature lambs. Materials and Methods: A sheep model of pregnancy was used in which the ileal mucosa, submucosa, and ENS were assessed following IA exposure to lipopolysaccharide (LPS) for 2 or 7 days (acute), Ureaplasma parvum (UP) for 42 days (chronic), or repetitive microbial exposure (42 days UP with 2 or 7 days LPS). Results: IA LPS exposure for 7 days or IA UP exposure for 42 days caused intestinal injury and inflammation in the mucosal and submucosal layers of the gut. Repetitive microbial exposure did not further aggravate injury of the terminal ileum. Chronic IA UP exposure caused significant structural ENS alterations characterized by loss of PGP9.5 and S100β immunoreactivity, whereas these changes were not found after re-exposure of chronic UP-exposed fetuses to LPS for 2 or 7 days. Conclusion: The in utero loss of PGP9.5 and S100β immunoreactivity following chronic UP exposure corresponds with intestinal changes in neonates with NEC and may therefore form a novel mechanistic explanation for the association of chorioamnionitis and NEC.

Infection-mediated preterm birth: Bacterial origins and avenues for intervention

Preterm birth (PTB) is globally the leading cause of death and disability in children under five years of age. Intra-amniotic infection is well recognised as a major cause of PTB. Importantly, it is the most common cause of extreme PTB (birth prior to 28 weeks gestation), which is frequently associated with a wide range of serious neonatal morbidities. Recent developments in next generation sequencing technologies, combined with many years of culture-based microbiological data have allowed us to gain a deeper understanding of the pathogenesis of infection-mediated PTB. In particular, studies have revealed numerous potential routes to intra-amniotic infection beyond the classically described ascending vaginal route. Currently, antibiotic therapy is standard treatment for suspected or confirmed intra-amniotic infection, although its use in this context has had mixed success due to problems ranging from inappropriate antibiotic selection in relation to the target organism/s, to poor transplacental drug passage. In this review, we will draw together evidence from animal models and human studies to characterise pathways to intra-amniotic infection. We will then thoroughly outline current therapeutic protocols for cases of intra-amniotic infection and suggest potential new avenues for treatment.

Patients with acute cervical insufficiency without intra-amniotic infection/inflammation treated with cerclage have a good prognosis

Background The frequency of intra-amniotic infection/inflammation (IAI/I) in patients with midtrimester cervical insufficiency is up to 50%. Our purpose was to determine the perinatal outcomes of cervical cerclage in patients with acute cervical insufficiency with bulging membranes, and to compare the admission-to-delivery interval and pregnancy outcomes according to the results of amniotic fluid (AF) analysis and cerclage placement. Methods This was a retrospective cohort study including singleton pregnancies with cervical insufficiency between 15 and 26.9 weeks in two tertiary health centers. IAI/I was defined when at least one of the following criteria was present in AF: (a) a white blood cell (WBC) count >50 cells/mm3; (b) glucose concentration <14 mg/dL; and/or (c) a Gram stain positive for bacteria. Three different groups were compared: (1) absence of IAI/I with placement of a cerclage; (2) amniocentesis not performed with placement of a cerclage; and (3) IAI/I with or without a cerclage. Results Seventy patients underwent an amniocentesis to rule out IAI/I. The prevalence of IAI/I was 19%. Forty-seven patients underwent a cerclage. Patients with a cerclage had a longer median admission-to-delivery interval (33 vs. 2 days; P < 0.001) and delivered at a higher median gestational age (27.4 vs. 22.6 weeks; P = 0.001) than those without a cerclage. The neonatal survival rate in the cerclage group was 62% vs. 23% in those without a cerclage (P = 0.01). Patients without IAI/I who underwent a cerclage had a longer median admission-to-delivery interval (43 vs. 1 day; P < 0.001), delivered at a higher median gestational age (28 vs. 22.1 weeks; P = 0.001) and had a higher neonatal survival rate (67% vs. 8%; P < 0.001) than those with IAI/I. Conclusion The pregnancy outcomes of patients with midtrimester cervical insufficiency and bulging membranes are poor as they have a high prevalence of IAI/I. Therefore, a pre-operative amniocentesis is key to identify the best candidates for the subsequent placement of a cerclage.

The earlier the gestational age, the greater the intensity of the intra-amniotic inflammatory response in women with preterm premature rupture of membranes and amniotic fluid infection by Ureaplasma species

Objectives To determine the relationship between the intensity of the intra-amniotic inflammatory response and the gestational age at the time of diagnosis in cases with preterm premature rupture of membranes (PROM) and intra-amniotic infection caused by Ureaplasma spp. Methods A retrospective cohort study was conducted which included 71 women with preterm PROM and a positive amniotic fluid culture with Ureaplasma spp. Women with mixed intra-amniotic infections were excluded. The study population was classified into three groups according to gestational age: group 1, <26 weeks (extreme preterm PROM, n = 17); group 2, 26.0-33.9 weeks (moderate preterm PROM, n = 39); group 3, 34.0-36.9 weeks (late preterm PROM, n = 15). The intensity of the intra-amniotic and maternal inflammatory response was compared among the three groups. The intensity of the intra-amniotic inflammatory response was assessed by the concentration of amniotic fluid matrix metalloproteinase-8 (MMP-8) and white blood cell (WBC) count. The maternal inflammatory response was assessed by the concentration of C-reactive protein (CRP) and WBC count in maternal blood at the time of amniocentesis. Results (1) The median values of amniotic fluid MMP-8 concentration and WBC count were the highest in the extreme preterm PROM group and the lowest in the late preterm PROM group (P < 0.001 and P = 0.01, respectively); (2) the intensity of the maternal inflammatory response measured by maternal blood WBC count and CRP concentration was not significantly associated with gestational age at the time of diagnosis. Conclusion The earlier the gestational age at the time of PROM, the higher the intensity of the intra-amniotic inflammatory response in women with preterm PROM and intra-amniotic infection caused by Ureaplasma spp.

Should the diagnostic criteria for suspected clinical chorioamnionitis be changed?

Purpose of review: The criteria for the diagnosis of intra-amniotic infection (IAI) were derived from a study of women at term in labor but is currently used as the main diagnostic tool for clinical chorioamnionitis. Regarding the inconsistent usage of the term, the diagnostic utility of clinical chorioamnionitis needs to be revisited. In this review, we addressed the critical issues on why the diagnostic criteria of suspected clinical chorioamnionitis should be changed.Recent findings: Overall, the accuracy of clinical chorioamnionitis to detect intra-amniotic infection (IAI) is not high, around 50%. The accuracy of each diagnostic criteria to diagnose IAI is, for example, 51.1% with maternal tachycardia, 57.8% with fetal tachycardia, and 55.6% with maternal leukocytosis. However, it needs to be reminded that these diagnostic performances had been obtained from term pregnancies but not from preterm pregnancies. Since there is a difference between clinical chorioamnionitis and histologic chorioamnionitis or even IAI, the diagnostic criteria of clinical chorioamnionitis would be ideal if it could directly predict the development of neonatal infectious outcomes. In fact, multiple definitions of clinical chorioamnionitis either in more lenient or stringent manner are currently used, which is responsible for inconsistent association of clinical chorioamnionitis with long-term neonatal outcomes. Whereas the diagnosis of clinical chorioamnionitis in preterm is followed by expeditious delivery, the diagnosis of clinical chorioamnionitis at term pregnancy is usually conducted in laboring women and requires additional neonatal evaluation for sepsis, which suggests different implications of clinical chorioamnionitis in preterm and term pregnancy.Summary: Current diagnostic criteria of clinical chorioamnionitis should be revised, specifically in terms of sensitivity in preterm pregnancy and specificity in term pregnancy.

Nicotinamide phosphoribosyltransferase and intra-amniotic inflammation in preterm prelabor rupture of membranes

Introduction: The amniotic fluid nicotinamide phosphoribosyltransferase (NAMPT) levels have not been compared among women with preterm prelabor rupture of membranes (PPROM) comorbid with intra-amniotic infection, sterile intra-amniotic inflammation (IAI), colonization, or without IAI and microbial invasion of the amniotic cavity (MIAC). Therefore, the main aim was to quantify the amniotic fluid NAMPT in women with PPROM complicated by intra-amniotic infection, sterile IAI, or colonization. The second aim was to characterize the diagnostic indices of NAMPT to reveal IAI. The third aim was to determine whether the cervical fluid and maternal serum NAMPT quantitation might be of value in the identification of intra-amniotic inflammatory complications in PPROM.Methods of study: NAMPT levels in amniotic fluid, cervical fluid, and maternal serum were assessed in three independent cohorts of women with singleton pregnancies complicated by PPROM between 24⁺⁰ and 36⁺⁶ weeks of gestation consisting of 88, 121, and 88 women, respectively. Amniotic fluid samples were obtained by transabdominal amniocentesis, cervical fluid samples were obtained using a Dacron polyester swab and maternal blood was obtained by venipuncture of the cubital vein. The NAMPT levels were measured by an enzyme-linked immunosorbent assay. Testing for MIAC and IAI was performed on all women, who were then categorized into four subgroups: intra-amniotic infection (MIAC and IAI), sterile IAI (IAI alone), colonization (MIAC alone), and without MIAC and IAI.Results: Women with intra-amniotic infection and women with sterile IAI had higher NAMPT levels than did women with colonization and women without MIAC and IAI (intra-amniotic infection: median 73.6 ng/mL, sterile IAI: median 55.5 ng/mL, colonization: median 12.1 ng/mL, without MIAC and IAI: 10.6 ng/mL; p < .0001). An amniotic fluid NAMPT level of 37 ng/mL was the best value for the detection of intra-amniotic infection in women with PPROM. Cervical fluid (p = .51) and maternal serum (p = .50) NAMPT levels did not reflect intra-amniotic inflammatory complications in women with PPROM.Conclusions: Intra-amniotic infection and sterile IAI are associated with higher NAMPT levels in amniotic fluid but not in cervical fluid or maternal serum in women with PPROM. Amniotic fluid NAMPT might be a marker for invasive identification of IAI in PPROM.

Clinical chorioamnionitis at term IX: in vivo evidence of intra-amniotic inflammasome activation

Background The inflammasome has been implicated in the mechanisms that lead to spontaneous labor at term. However, whether the inflammasome is activated in the amniotic cavity of women with clinical chorioamnionitis at term is unknown. Herein, by measuring extracellular ASC [apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (CARD)], we investigated whether there is in vivo inflammasome activation in amniotic fluid of patients with clinical chorioamnionitis at term with sterile intra-amniotic inflammation and in those with intra-amniotic infection. Methods This was a retrospective cross-sectional study that included amniotic fluid samples collected from 76 women who delivered after spontaneous term labor with diagnosed clinical chorioamnionitis. Intra-amniotic inflammation was defined as an elevated amniotic fluid interleukin (IL)-6 concentration ≥2.6 ng/mL, and intra-amniotic infection was diagnosed by the presence of microbial invasion of the amniotic cavity (MIAC) accompanied by intra-amniotic inflammation. Patients were classified into the following groups: (1) women without intra-amniotic inflammation or infection (n=16); (2) women with MIAC but without intra-amniotic inflammation (n=5); (3) women with sterile intra-amniotic inflammation (n=15); and (4) women with intra-amniotic infection (n=40). As a readout of in vivo inflammasome activation, extracellular ASC was measured in amniotic fluid by enzyme-linked immunosorbent assay. Acute inflammatory responses in the amniotic fluid and placenta were also evaluated. Results In clinical chorioamnionitis at term: (1) amniotic fluid concentrations of ASC (extracellular ASC is indicative of in vivo inflammasome activation) and IL-6 were greater in women with intra-amniotic infection than in those without intra-amniotic inflammation, regardless of the presence of MIAC; (2) amniotic fluid concentrations of ASC and IL-6 were also higher in women with sterile intra-amniotic inflammation than in those without intra-amniotic inflammation, regardless of the presence of MIAC; (3) amniotic fluid concentrations of IL-6, but not ASC, were more elevated in women with intra-amniotic infection than in those with sterile intra-amniotic inflammation; (4) a positive and significant correlation was observed between amniotic fluid concentrations of ASC and IL-6; (5) no differences were observed in amniotic fluid ASC and IL-6 concentrations between women with and without MIAC in the absence of intra-amniotic inflammation; (6) women with intra-amniotic infection had elevated white blood cell counts and reduced glucose levels in amniotic fluid compared to the other three study groups; and (7) women with intra-amniotic infection presented higher frequencies of acute maternal and fetal inflammatory responses in the placenta than those with sterile intra-amniotic inflammation. Conclusion The intra-amniotic inflammatory response, either induced by alarmins or microbes, is characterized by the activation of the inflammasome - as evidenced by elevated amniotic fluid concentrations of extracellular ASC - in women with clinical chorioamnionitis at term. These findings provide insight into the intra-amniotic inflammatory response in women with clinical chorioamnionitis at term.

A high concentration of fetal fibronectin in cervical secretions increases the risk of intra-amniotic infection and inflammation in patients with preterm labor and intact membranes

Objective To determine whether the risk of intra-amniotic infection/inflammation and spontaneous preterm delivery (SPTD) varies as a function of the concentration of cervical fetal fibronectin (fFN) in patients with preterm labor and intact membranes. Methods This prospective study included 180 patients with preterm labor and intact membranes who had a sample collected for quantitative fFN measurement and underwent amniocentesis. Amniotic fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas. Intra-amniotic inflammation was defined as an amniotic fluid matrix metalloproteinase-8 concentration >23 ng/mL. Results (1) The prevalence of intra-amniotic infection/inflammation and SPTD within 7 days was 32.2% (58/180) and 33.9% (61/178), respectively; (2) The higher the fFN concentration, the greater the risk of intra-amniotic infection/inflammation and SPTD within 7 days (P<0.001, respectively); (3) An fFN concentration 150 ng/mL had a better diagnostic performance than an fFN 50 ng/mL in the identification of intra-amniotic infection/inflammation and SPTD within 7 days; (4) Among the patients with an fFN <50 ng/mL, intra-amniotic infection/inflammation was identified in 7.6% (6/79) of patients and 66.7% (4/6) delivered within 7 days. Conclusion The higher the concentration of fFN, the greater the risk of intra-amniotic infection/inflammation and SPTD in patients with preterm labor and intact membranes.

Oral and uro-vaginal intra-amniotic infection in women with preterm delivery: A case-control study

AIM

The aim of the present study was to establish the association between the presence of oral and uro-vaginal microorganisms in the placental membrane and preterm delivery (PTD), the premature rupture of membranes (PRM), and the clinical signs of intra-amniotic infection.

METHODS

Eighty-four women with PTD and 127 women with delivery at term were assessed for the PRM, clinical signs of intra-amniotic infection, and the presence of periodontitis. Twenty-seven microorganisms were identified in the placental tissue using nested polymerase chain reaction (PCR). Porphyromonas gingivalis (P. gingivalis) was quantified by droplet digital PCR.

RESULTS

The prevalence of microorganisms was 9.47% (20/211). P. gingivalis was the most prevalent (12/211, 5.68%). Mycoplasma hominis, Ureaplasma urealyticum, Staphylococcus spp, and Fusobacterium nucleatum were isolated at a very low frequency in the placenta. Candida albicans was associated with PTD (P = 0.027). Periodontitis was associated with clinical signs of infection (odds ratio [OR] = 3.8, 95% confidence interval [CI]: 1.28-13.5) and with PTD (OR = 1.99; 95% CI: 1.07-3.72).

CONCLUSION

The presence of P. gingivalis in the placenta was not associated with perinatal complications. Detecting microorganisms in the placenta by nested PCR is not relevant, as it has a poor association with clinical variables that establish the diagnosis of chorioamnionitis. However, periodontitis was associated with the clinical signs of intra-amniotic infection and PTD.

Risk of intra-amniotic infection/inflammation and respiratory distress syndrome according to the birth order in twin preterm neonates

Objective: Prior studies have suggested that nonpresenting twins are more likely to develop respiratory distress syndrome (RDS) than presenting twins. While the underlying mechanism is not known, exposure to intra-amniotic infection/inflammation (IAI) has been associated with a reduced risk of RDS in singleton gestations. In the current study, we compared the risk of RDS in preterm twin neonates according to birth order with adjustment for the presence or absence of IAI.Methods: The study population consisted of consecutive twin neonates who delivered ≤35 weeks and underwent amniocentesis within 7 days of delivery. The frequency of RDS and IAI was compared between presenting and nonpresenting twin pairs. Amniotic fluid (AF) was cultured for aerobic/anaerobic bacteria and genital mycoplasma. IAI was defined as a positive AF culture or an AF white cell count ≥19/mm³.Results: A total of 120 twin pairs were enrolled. Compared with presenting twins, nonpresenting twins had a lower risk of IAI (36 vs. 26%, respectively, p < .05), but a higher risk of RDS (18 vs. 25%, respectively, p < .05). In multivariate analysis, only IAI remained significantly associated with RDS (OR 0.18, 95% CI 0.05-0.65), whereas birth order was not.Conclusions: In preterm twin neonates, the increased risk of RDS in nonpresenting twins is likely due to lower exposure to IAI and not birth order.

The frequency and type of placental histologic lesions in term pregnancies with normal outcome

Objective To determine the frequency and type of histopathologic lesions in placentas delivered by women with a normal pregnancy outcome. Methods This retrospective cohort study included placental samples from 944 women with a singleton gestation who delivered at term without obstetrical complications. Placental lesions were classified into the following four categories as defined by the Society for Pediatric Pathology and by our unit: (1) acute placental inflammation, (2) chronic placental inflammation, (3) maternal vascular malperfusion and (4) fetal vascular malperfusion. Results (1) Seventy-eight percent of the placentas had lesions consistent with inflammatory or vascular lesions; (2) acute inflammatory lesions were the most prevalent, observed in 42.3% of the placentas, but only 1.0% of the lesions were severe; (3) acute inflammatory lesions were more common in the placentas of women with labor than in those without labor; (4) chronic inflammatory lesions of the placenta were present in 29.9%; and (5) maternal and fetal vascular lesions of malperfusion were detected in 35.7% and 19.7%, respectively. Two or more lesions with maternal or fetal vascular features consistent with malperfusion (high-burden lesions) were present in 7.4% and 0.7%, respectively. Conclusion Most placentas had lesions consistent with inflammatory or vascular lesions, but severe and/or high-burden lesions were infrequent. Mild placental lesions may be interpreted either as acute changes associated with parturition or as representative of a subclinical pathological process (intra-amniotic infection or sterile intra-amniotic inflammation) that did not affect the clinical course of pregnancy.

Mid-trimester preterm premature rupture of membranes (PPROM): etiology, diagnosis, classification, international recommendations of treatment options and outcome

Mid-trimester preterm premature rupture of membranes (PPROM), defined as rupture of fetal membranes prior to 28 weeks of gestation, complicates approximately 0.4%-0.7% of all pregnancies. This condition is associated with a very high neonatal mortality rate as well as an increased risk of long- and short-term severe neonatal morbidity. The causes of the mid-trimester PPROM are multifactorial. Altered membrane morphology including marked swelling and disruption of the collagen network which is seen with PPROM can be triggered by bacterial products or/and pro-inflammatory cytokines. Activation of matrix metalloproteinases (MMP) have been implicated in the mechanism of PPROM. The propagation of bacteria is an important contributing factor not only in PPROM, but also in adverse neonatal and maternal outcomes after PPROM. Inflammatory mediators likely play a causative role in both disruption of fetal membrane integrity and activation of uterine contraction. The "classic PPROM" with oligo/an-hydramnion is associated with a short latency period and worse neonatal outcome compared to similar gestational aged neonates delivered without antecedent PPROM. The "high PPROM" syndrome is defined as a defect of the chorio-amniotic membranes, which is not located over the internal cervical os. It may be associated with either a normal or reduced amount of amniotic fluid. It may explain why sensitive biochemical tests such as the Amniosure (PAMG-1) or IGFBP-1/alpha fetoprotein test can have a positive result without other signs of overt ROM such as fluid leakage with Valsalva. The membrane defect following fetoscopy also fulfils the criteria for "high PPROM" syndrome. In some cases, the rupture of only one membrane - either the chorionic or amniotic membrane, resulting in "pre-PPROM" could precede "classic PPROM" or "high PPROM". The diagnosis of PPROM is classically established by identification of nitrazine positive, fern positive watery leakage from the cervical canal observed during in specula investigation. Other more recent diagnostic tests include the vaginal swab assay for placental alpha macroglobulin-1 test or AFP and IGFBP1. In some rare cases amniocentesis and infusion of indigo carmine has been used to confirm the diagnosis of PPROM. The management of the PPROM requires balancing the potential neonatal benefits from prolongation of the pregnancy with the risk of intra-amniotic infection and its consequences for the mother and infant. Close monitoring for signs of chorioamnionitis (e.g. body temperature, CTG, CRP, leucocytes, IL-6, procalcitonine, amniotic fluid examinations) is necessary to minimize the risk of neonatal and maternal complications. In addition to delayed delivery, broad spectrum antibiotics of penicillin or cephalosporin group and/or macrolide and corticosteroids have been show to improve neonatal outcome [reducing risk of chorioamnionitis (average risk ratio (RR)=0.66), neonatal infections (RR=0.67) and abnormal ultrasound scan of neonatal brain (RR=0.67)]. The positive effect of continuous amnioinfusion through the subcutaneously implanted perinatal port system with amniotic fluid like hypo-osmotic solution in "classic PPROM" less than 28/0 weeks' gestation shows promise but must be proved in future prospective randomized studies. Systemic antibiotics administration in "pre-PPROM" without infection and hospitalization are also of questionable benefit and needs to be further evaluated in well-designed randomized prospective studies to evaluate if it is associated with any neonatal benefit as well as the relationship to possible adverse effect of antibiotics on to fetal development and neurological outcome.

Parallel detection of lactobacillus and bacterial vaginosis-associated bacterial DNA in the chorioamnion and vagina of pregnant women at term

BACKGROUND

The majority of early preterm births are associated with intrauterine infections, which are thought to occur when microbes traffic into the uterus from the lower genital tract and seed the placenta. Bacterial vaginosis (BV) is associated with heterogeneous bacterial communities in the vagina and is linked to preterm birth. The extent to which trafficking into the uterus of normal and BV-associated vaginal bacteria occurs is unknown. The study objective was to characterize in parallel the distribution and quantities of bacteria in the vagina, uterus, and placental compartments.

METHODS

Pregnant women at term (≥37 weeks) presenting for delivery were recruited prospectively. Swabs were collected in parallel from the vagina, chorioamnion. Choriodecidual swabs were collected if a cesarean section was performed. Samples were analyzed by culture, broad-range 16S rRNA gene PCR, and bacterial species-specific quantitative PCR (qPCR) for DNA from Lactobacillus and a panel of BV-associated bacteria. Results were correlated with placental histopathology.

RESULTS

Of the 23 women enrolled, 15 were delivered by cesarean section (N = 10 without labor; N = 5 in labor) and eight were delivered vaginally. BV was diagnosed in two women not in labor. Placental histopathology identified chorioamnionitis or funisitis in six cases [1/10 (10%) not in labor; 5/13 (38%) in labor]. Among non-laboring women, broad-range 16S qPCR detected bacteria in the chorioamnion and the choriodecidua (4/10; 40%). Among laboring women, Lactobacillus species were frequently detected in the chorioamnion by qPCR (4/13; 31%). In one case, mild chorioamnionitis was associated with qPCR detection of similar microbes in the chorioamnion and vagina (e.g. Leptotrichia/Sneathia, Megasphaera), along a quantitative gradient.

CONCLUSIONS

Microbial trafficking of lactobacilli and fastidious bacteria into the chorioamniotic membranes and choriodecidua occurs at term in normal pregnancies. In one case, we demonstrated a quantitative gradient between multiple bacterial species in the lower genital tract and placenta. Not all bacterial colonization is associated with placental inflammation and clinical sequelae. Further studies of the role of placental colonization with Lactobacillus in normal pregnancy and fastidious bacteria in chorioamnionitis may improve prevention and treatment approaches for preterm labor.

The immunophenotype of amniotic fluid leukocytes in normal and complicated pregnancies

PROBLEM

The immune cellular composition of amniotic fluid is poorly understood. Herein, we determined: 1) the immunophenotype of amniotic fluid immune cells during the second and third trimester in the absence of intra-amniotic infection/inflammation; 2) whether amniotic fluid T cells and ILCs display different phenotypical characteristics to that of peripheral cells; and 3) whether the amniotic fluid immune cells are altered in women with intra-amniotic infection/inflammation.

METHOD OF STUDY

Amniotic fluid samples (n = 57) were collected from 15 to 40 weeks of gestation in women without intra-amniotic infection/inflammation. Samples from women with intra-amniotic infection/inflammation were also included (n = 9). Peripheral blood mononuclear cells from healthy adults were used as controls (n = 3). Immunophenotyping was performed using flow cytometry.

RESULTS

In the absence of intra-amniotic infection/inflammation, the amniotic fluid contained several immune cell populations between 15 and 40 weeks. Among these immune cells: (i) T cells and ILCs were greater than B cells and natural killer (NK) cells between 15 and 30 weeks; (ii) T cells were most abundant between 15 and 30 weeks; (iii) ILCs were most abundant between 15 and 20 weeks; (iv) B cells were scarce between 15 and 20 weeks; yet, they increased and were constant after 20 weeks; (v) NK cells were greater between 15 and 30 weeks than at term; (vi) ILCs expressed high levels of RORγt, CD161, and CD103 (ie, group 3 ILCs); (vii) T cells expressed high levels of RORγt; (viii) neutrophils increased as gestation progressed; and (ix) monocytes/macrophages emerged after 20 weeks and remained constant until term. All of the amniotic fluid immune cells, except ILCs, were increased in the presence of intra-amniotic infection/inflammation.

CONCLUSION

The amniotic fluid harbors a diverse immune cellular composition during normal and complicated pregnancies.

Granulocytic myeloid-derived suppressor cells (GR-MDSC) accumulate in cord blood of preterm infants and remain elevated during the neonatal period

Preterm delivery is the leading cause of perinatal morbidity and mortality. Among the most important complications in preterm infants are peri- or postnatal infections. Myeloid-derived suppressor cells (MDSC) are myeloid cells with suppressive activity on other immune cells. Emerging evidence suggests that granulocytic MDSC (GR-MDSC) play a pivotal role in mediating maternal-fetal tolerance. The role of MDSC for postnatal immune-regulation in neonates is incompletely understood. Until the present time, nothing was known about expression of MDSC in preterm infants. In the present pilot study, we quantified GR-MDSC counts in cord blood and peripheral blood of preterm infants born between 23 + 0 and 36 + 6 weeks of gestation (WOG) during the first 3 months of life and analysed the effect of perinatal infections. We show that GR-MDSC are increased in cord blood independent of gestational age and remain elevated in peripheral blood of preterm infants during the neonatal period. After day 28 they drop to nearly adult levels. In case of perinatal or postnatal infection, GR-MDSC accumulate further and correlate with inflammatory markers C-reactive protein (CRP) and white blood cell counts (WBC). Our results point towards a role of GR-MDSC for immune-regulation in preterm infants and render them as a potential target for cell-based therapy of infections in these patients.

Amniotic fluid neutrophils can phagocytize bacteria: A mechanism for microbial killing in the amniotic cavity

PROBLEM

Neutrophils are capable of performing phagocytosis, a primary mechanism for microbial killing. Intra-amniotic infection is characterized by an influx of neutrophils into the amniotic cavity. Herein, we investigated whether amniotic fluid neutrophils could phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection.

METHODS

Amniotic fluid neutrophils from women with intra-amniotic infection were visualized by transmission electron microscopy (n=6). The phagocytic activity of amniotic fluid neutrophils from women with intra-amniotic infection and/or inflammation (n=10) or peripheral neutrophils from healthy individuals (controls, n=3) was tested using ex vivo phagocytosis assays coupled with live imaging. Phagocytosis by amniotic fluid neutrophils was also visualized by confocal microscopy (n=10) as well as scanning and transmission electron microscopy (n=5).

RESULTS

(i) Intra-amniotic infection-related bacteria including cocci (eg Streptococcus agalactiae), bacilli (eg Bacteriodes fragilis and Prevotella spp.), and small bacteria without a cell wall (eg Ureaplasma urealyticum) were found inside of amniotic fluid neutrophils; (ii) peripheral neutrophils (controls) rapidly phagocytized S. agalactiae, U. urealyticum, Gardnerella vaginalis, and Escherichia coli; (iii) amniotic fluid neutrophils rapidly phagocytized S. agalactiae and G. vaginalis; and (iv) amniotic fluid neutrophils slowly phagocytized U. urealyticum and E. coli; yet, the process of phagocytosis of the genital mycoplasma was lengthier.

CONCLUSION

Amniotic fluid neutrophils can phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection, namely S. agalactiae, U. urealyticum, G. vaginalis, and E. coli. Yet, differences in the rapidity of phagocytosis were observed among the studied microorganisms. These findings provide a host defense mechanism whereby amniotic fluid neutrophils can kill microbes invading the amniotic cavity.

A Role for the Inflammasome in Spontaneous Labor at Term with Acute Histologic Chorioamnionitis

Inflammasomes are cytosolic signaling platforms that regulate the activation of caspase (CASP)-1, which induces the maturation of interleukin (IL)-1β and IL-18. Herein, we determined whether the chorioamniotic membranes from women in spontaneous labor at term with acute histologic chorioamnionitis express major inflammasome components and whether these changes are associated with the activation of CASP-1 and CASP-4 and the release of mature IL-1β and IL-18. When comparing the chorioamniotic membranes from women in spontaneous labor at term with acute histologic chorioamnionitis to those without this placental lesion, we found that (1) the messenger RNA (mRNA) abundance of NLR family pyrin domain containing 3 ( NLRP3), NLR family CARD domain containing 4 ( NLRC4), absent in melanoma 2 ( AIM2), and nucleotide binding oligomerization domain 2 ( NOD2) was higher; (2) the NLRP3 and NLRC4 protein quantities were increased; (3) the mRNA and protein expressions of CASP-1 and its active forms were greater; (4) CASP-4 was increased at the mRNA level only; (5) the mRNA and protein expressions of IL-1β and its mature form were higher; and (6) a modest increase in the total protein concentration and abundance of the mature form of IL-18 was observed. In vitro incubation of the chorioamniotic membranes with the CASP-1 inhibitor, VX765, decreased the release of endotoxin-induced IL-1β and IL-18 (2-fold) but not IL-6 or tumor necrosis factor α. In conclusion, spontaneous labor at term with acute histologic chorioamnionitis is characterized by an upregulation of inflammasome components which, in turn, may participate in the activation of CASP-1 and lead to the release of mature IL-1β by the chorioamniotic membranes. These results support a role for the inflammasome in the mechanisms responsible for spontaneous labor at term with acute histologic chorioamnionitis.

Procalcitonin is more likely to be released by the fetus rather than placental tissue during chorioamnionitis

AIMS

To analyze the relationship between maternal, cord blood and neonatal procalcitonin (PCT) levels in preterm deliveries with and without histologically proven chorioamnionitis (HCA).

METHODS

91 mother-infant pairs from 24+0 to 33+0 gestational weeks were analyzed. Procalcitonin was measured in all mothers within 24 hours before and subsequently in cord blood and in neonates within the first two hours after delivery. PCT levels were analysed in relationship to HCA and clinical outcome.

RESULTS

HCA was confirmed in 28 cases (31%). We found no differences in PCT values between HCA positive and negative groups in maternal blood (0.1±0.1 vs 0.09±0.09 ng/L, P = 0.76). PCT values in cord blood and neonates were significantly higher in the HCA positive compared to HCA negative group (0.23±0.1 vs 1.2±2.7 ng/L, P < 0.001 and 0.89±3.4 vs 4.2±9.3 ng/L, P < 0.0001 respectively). PCT values in neonates were significantly higher than those of cord blood. Levels were not influenced by the mode of delivery, gestational age or premature rupture of membranes. Chorioamnionitis was more frequently associated with early onset neonatal sepsis (36% in HCA group vs 5% in non HCA group, P < 0.0001). Comparison of other clinical data revealed no differences between HCA positive and negative groups.

CONCLUSION

This study showed higher PCT in cord and neonatal blood in the presence of proven histological chorioamnionitis. The measurement of PCT in mothers' blood is not helpful for diagnosis of HCA. The changes in PCT values shown suggest its production and release by fetal tissue.

Polymicrobial Amniotic Fluid Infection with Mycoplasma/Ureaplasma and Other Bacteria Induces Severe Intra-Amniotic Inflammation Associated with Poor Perinatal Prognosis in Preterm Labor

PROBLEM

To study the relationship between perinatal prognosis in cases of preterm labor (PTL) and polymicrobial infection in amniotic fluid (AF) and intra-amniotic (IA) inflammation using a highly sensitive and reliable PCR-based method.

METHOD OF STUDY

To detect prokaryotes using a nested PCR-based method, eukaryote-made thermostable DNA polymerase without bacterial DNA contamination was used in combination with bacterial universal primers. We collected AF aseptically from 118 PTL cases and 50 term subjects.

RESULTS

The prevalence of microorganisms was 33% (39/118) by PCR and only 7.6% (9/118) by culture. PTL caused by a combination of positive Mycoplasma/Ureaplasma and other bacteria had significantly higher AF IL-8 levels and a significantly shorter amniocentesis-to-delivery interval.

CONCLUSIONS

Our newly established PCR method is useful for detecting IA microorganisms. Polymicrobial infection with Mycoplasma/Ureaplasma and other bacteria induces severe IA inflammation associated with poor perinatal prognosis in PTL.

Amniotic fluid sludge as a marker of intra-amniotic infection and histological chorioamnionitis in cervical insufficiency: a report of four cases and literature review

Amniotic fluid sludge (AFS) is defined as the presence of particulate matter in the amniotic fluid in close proximity to the cervix. Although its prevalence is known to correlate with the risk of preterm delivery, initial reports describe a strong association between AFS and microbial invasion of the amniotic cavity (MIAC) and histological chorioamnionitis. However, AFS is also present in uncomplicated pregnancies, and its prevalence appears to increase with gestational age. Recent evidence debates the usefulness of AFS as a marker of early preterm delivery risk. We present four cases with AFS diagnosed by transvaginal ultrasound at admission for cervical insufficiency between 20 and 24 weeks of gestation, with confirmed lower genital tract and intra-amniotic infections by amniocentesis and histological chorioamnionitis and funisitis. Our findings reinforce the presence of AFS as a useful marker of MIAC, chorioamnionitis and funisitis that increase the likelihood of preterm delivery at an extreme gestational age.