A clinical prediction rule for histological chorioamnionitis in preterm newborns

Relationship between chorioamnionitis or funisitis and lung injury among preterm infants: meta-analysis involved 16 observational studies with 68,397 participants

BACKGROUND

Chorioamnionitis (CA) can cause multiple organ injuries in premature neonates, particularly to the lungs. Different opinions exist regarding the impact of intrauterine inflammation on neonatal respiratory distress syndrome (NRDS) and bronchopulmonary dysplasia (BPD). We aim to systematically review the relationship between CA or Funisitis (FV) and lung injury among preterm infants.

METHODS

We electronically searched PubMed, EMbase, the Cochrane library, CNKI, and CMB for cohort studies from their inception to March 15, 2023. Two reviewers independently screened literature, gathered data, and did NOS scale of included studies. The meta-analysis was performed using RevMan 5.3.

RESULTS

Sixteen observational studies including 68,397 patients were collected. Meta-analysis showed CA or FV increased the lung injury risk (OR = 1.43, 95%CI: 1.06-1.92). Except for histological chorioamnionitis (HCA) (OR = 0.72, 95%CI: 0.57-0.90), neither clinical chorioamnionitis (CCA) (OR = 1.86, 95%CI: 0.93-3.72) nor FV (OR = 1.23, 95%CI: 0.48-3.15) nor HCA with FV (OR = 1.85, 95%CI: 0.15-22.63) had statistical significance in NRDS incidence. As a result of stratification by grade of HCA, HCA (II) has a significant association with decreased incidence of NRDS (OR = 0.48, 95%CI: 0.35-0.65). In terms of BPD, there is a positive correlation between BPD and CA/FV (CA: OR = 3.18, 95%CI: 1.68-6.03; FV: OR = 6.36, 95%CI: 2.45-16.52). Among CA, HCA was positively associated with BPD (OR = 2.70, 95%CI: 2.38-3.07), whereas CCA was not associated with BPD (OR = 2.77, 95%CI: 0.68-11.21). HCA and moderate to severe BPD (OR = 25.38, 95%CI: 7.13-90.32) showed a positive correlation, while mild BPD (OR = 2.29, 95%CI: 0.99-5.31) did not.

CONCLUSION

Currently, evidence suggests that CA or FV increases the lung injury incidence in premature infants. For different types of CA and FV, HCA can increase the incidence of BPD while decreasing the incidence of NRDS. And this "protective effect" only applies to infants under 32 weeks of age. Regarding lung injury severity, only moderate to severe cases of BPD were positively correlated with CA.

Effect of preterm chorioamnionitis on lung ultrasound score used to guide surfactant replacement

OBJECTIVE

Lung ultrasound score (LUS) accurately guides surfactant replacement in preterm neonates with respiratory distress syndrome due to surfactant deficiency. However, surfactant deficiency is not the unique pathobiological feature, as there may be relevant lung inflammation, such as in certain cases of clinical chorioamnionitis (CC). We aim to investigate if CC influences LUS and ultrasound-guided surfactant treatment.

DESIGN

Retrospective (2017-2022), large, cohort study targeted to recruit a homogeneous population treated with unchanged respiratory care policy and lung ultrasound protocol. Patients with (CC+: 207) and without (CC-: 205) chorioamnionitis were analyzed with propensity score matching and subsequent additional multivariate adjustments.

RESULTS

LUS was identical at unmatched and matched comparisons. Consistently, at least one surfactant dose was given in 98 (47.3%) and 83 (40.5%) neonates in the CC+ and CC- matched cohorts, respectively (p = .210). Multiple doses were needed in 28 (13.5%) and 21 (10.2%) neonates in the CC+ and CC- cohorts, respectively (p = .373). Postnatal age at surfactant dosing was also similar. LUS was higher in patients who were diagnosed with neonatal acute respiratory distress syndrome (NARDS) (CC+ cohort: 10.3 (2.9), CC- cohort: 11.4 (2.6)), than in those without NARDS (CC+ cohort: 6.1 (3.7), CC- cohort: 6.2 (3.9); p < .001, for both). Surfactant use was more frequent in neonates with, than in those without NARDS (p < .001). Multivariate adjustments confirmed NARDS as the variable with greater effect size on LUS.

CONCLUSIONS

CC does not influence LUS in preterm neonates, unless inflammation is enough severe to trigger NARDS. The occurrence of NARDS is key factor influencing the LUS.

Clinical characteristics, complications, and predictive model of histological chorioamnionitis in women with preterm premature rupture of membranes

We aimed to analyze the impact of histological chorioamnionitis (HCA) in the presence of preterm premature rupture of the membranes (PPROM) on obstetric and neonatal outcomes, and its possible predictability. A retrospective cohort analysis of PPROM cases (20-37 weeks) was conducted comparing the patients with and without HCA, seeking a predictive model of HCA using logistic regression. A total of 295 cases of PPROM were selected, of which 72 (24.4%) had HCA. The group with HCA had a shorter latency period and a greater number of clinical and laboratory criteria in the evolution. The group with HCA had a worse comparative result and presented: lower gestational age at delivery, lower average birth weight, lower Apgar scores, longer neonatal hospitalization, worse maternal clinical conditions and, higher rates of stillbirth, low birth weight (LBW), very low birth weight (VLBW), complications in pregnancy and childbirth, and cesarean delivery due to fetal distress or chorioamnionitis. A predictive model for HCA was developed, with the following independent variables: abdominal pain (odds ratio [OR] = 11.61), uterine activity (noticeable contractions on physical exam) (OR = 5.97), fever (OR = 5.77), latency > 3 days (OR = 2.13), and C-reactive protein (OR = 1.01). With this model, an adequate receiver operating characteristic curve was found, with an area under the curve of 0.726, and some HCA probability curves were constructed for different clinical situations. In this novel study, we present a non-invasive predictive model, with clinical and laboratory variables, which may help in decision-making in a patient with PPROM.

Secretory phospholipase A2 expression and activity in preterm clinical chorioamnionitis with fetal involvement

Secretory phospholipase A2 (sPLA2) regulates the first step of inflammatory cascade and is involved in several pathological processes. sPLA2 also plays a role in preterm labor and parturition, since they are triggered by inflammatory mediators such as prostaglandins. Interestingly, chorioamnionitis (i.e.: the presence of intrauterine inflammation) is also often associated with preterm birth. We aimed to verify if chorioamnionitis with fetal involvement modifies sPLA2 activity and expression profile in mothers and neonates delivered prematurely. We collected maternal plasma and amniotic fluid, as well as bronchoalveolar lavage fluid from preterm neonates born to mothers with or without clinical chorioamnionitis with fetal involvement. We measured concentrations of sPLA2 subtype-IIA and -IB, total enzyme activity and proteins. Urea ratio was used to obtain epithelial lining fluid concentrations. Enzyme activity measured in maternal plasma (p<0.001) and amniotic fluid (p<0.001) was higher in chorioamnionitis cases than in controls. This was mainly due to the increased production of sPLA2-IIA as the subtype -IB was present in a smaller amount and was similar between the two groups; sPLA2-IIA was increased in epithelial lining fluid (p=0.045) or increased, although without statistical significance, in maternal plasma (p=0.06) and amniotic fluid (p=0.08) of chorioamnionitis cases. Cytokines known to increase sPLA2-IIA expression (TNF-a, IL-1b) or whose expression was increased by sPLA2-IIA (IL-8) were higher in histologically confirmed chorioamnionitis (TNF-a (p=0.028), IL-1b (p<0.001) and IL-8 (p=0.038)). These data represent the basis for future studies on sPLA2-IIA inhibition to prevent deleterious consequences of chorioamnionitis and preterm birth.

[Association of different stages of histological chorioamnionitis with respiratory distress syndrome in preterm infants with a gestational age of < 32 weeks]

OBJECTIVE

To study the association of different stages of histological chorioamnionitis (HCA) with the incidence rate and severity of respiratory distress syndrome (RDS) in preterm infants.

METHODS

Related data were collected from the infants and their mothers who were treated in the Neonatal Intensive Care Unit of Qingdao Women and Children's Hospital, Qingdao University, from January 2018 to June 2020. According to the presence or absence of HCA and its stage, the infants were divided into four groups: control (n=109), early-stage HCA (n=126), middle-stage HCA (n=105), and late-stage HCA (n=36). The four groups were compared in terms of gestational age, birth weight, sex, maternal age, placental abruption, prenatal use of antibiotics, and incidence rate of RDS. The correlation between HCA stage and RDS severity was analyzed.

RESULTS

Compared with the control and late-stage HCA groups, the early-stage HCA group had a significantly lower incidence rate of placental abruption and a significantly higher rate of prenatal use of antibiotics (P < 0.05), and the early-stage HCA group had a significantly lower incidence rate of RDS than the control group (P < 0.05). The multivariate logistic regression analysis showed that early-, middle-, and late-stage HCA were protective factors against RDS (P < 0.05). The Spearman test showed that the severity of RDS in preterm infants was not correlated with the HCA stage (P > 0.05).

CONCLUSIONS

Early-, middle-, and late-stage HCA can reduce the incidence rate of RDS in preterm infants. HCA stage may not be correlated with RDS severity in preterm infants, which needs to be verified by further research.

Detection of Volatile Organic Compounds as Potential Novel Biomarkers for Chorioamnionitis - Proof of Experimental Models

Background: Histologic chorioamnionitis is only diagnosed postnatally which prevents interventions. We hypothesized that volatile organic compounds (VOCs) in the amniotic fluid might be useful biomarkers for chorioamnionitis and that VOC profiles differ between amnionitis of different origins. Methods: Time-mated ewes received intra-amniotic injections of media or saline (controls), or live Ureaplasma parvum serovar 3 (Up) 14, 7 or 3d prior to c-section at day 124 gestational age (GA). 100 μg recombinant ovine IL-1α was instilled at 7, 3 or 1d prior to delivery. Headspace VOC profiles were measured from amniotic fluids at birth using ion mobility spectrometer coupled with multi-capillary columns. Results: 127 VOC peaks were identified. 27 VOCs differed between samples from controls and Up- or IL-1α induced amnionitis. The best discrimination between amnionitis by Up vs. IL-1α was reached by 2-methylpentane, with a sensitivity/specificity of 96/95% and a positive predictive value/negative predictive values of 96 and 95%. The concentration of 2-methylpentane in VOCs peaked 7d after intra-amniotic instillation of Up. Discussion: We established a novel method to study headspace VOC profiles of amniotic fluids. VOC profiles may be a useful tool to detect and to assess the duration of amnionitis induced by Up. 2-methylpentane was previously described in the exhalate of women with pre-eclampsia and might be a volatile biomarker for amnionitis. Amniotic fluids analyzed by ion mobility spectrometry coupled with multi-capillary columns may provide bedside diagnosis of amnionitis and understanding inflammatory mechanisms during pregnancy.

Impact of chorioamnionitis on maternal and fetal levels of proinflammatory S100A12

Histologic chorioamnionitis (HCA) may lead to the fetal inflammatory response syndrome (FIRS). The aim of this pilot study was to evaluate S100A12, a marker of innate immune activation, in mothers with or without HCA and in their infants. Concentrations of S100A12, interleukin 6 (IL-6), and C-reactive protein (CRP) were evaluated in maternal, cord, and neonatal blood of very preterm infants. Histologic examinations of the placenta and umbilical cords were performed. The 48 mother-neonate pairs enrolled were subdivided into two groups: HCA group (N = 15) and control group without HCA (N = 33). Maternal S100A12 levels were similar between HCA and control group. Similarly, S100A12 concentrations in cord and neonatal blood did not differ between the groups. However, high S100A12 concentrations were detected in cord and neonatal blood of two out of three neonates exposed to HCA associated with advanced funisitis. Concentrations of IL-6 and CRP were higher in maternal blood of the HCA group compared with controls (p < 0.05, p < 0.001; respectively), but no differences in cord or neonatal blood was found.Conclusion:S100A12 did neither identify mothers with HCA nor very preterm infants exposed to HCA. It is currently unknown if S100A12 may identify neonates with FIRS. What is known: • Histologic chorioamnionitis (HCA) may lead to the fetal inflammatory response syndrome (FIRS). • S100A12 represents an early, sensitive, and specific diagnostic marker of inflammatory processes. What is new: • S100A12 did neither identify mothers with HCA nor very preterm infants exposed to HCA. • It is currently still unclear if S100A12 has a potential in identifying preterm infants with FIRS.

Maternal risk score for the prediction of fetal inflammatory response syndrome after preterm premature rupture of membranes

AIM

Preterm premature rupture of membranes (PPROM) is common in preterm births. Fetal inflammatory response syndrome (FIRS) is present in nearly 50% of PPROM cases. We created a risk score to predict FIRS using maternal factors after PPROM.

METHODS

We conducted a retrospective study of singleton pregnancies complicated by PPROM that resulted in delivery at 23-35 weeks of gestation. Antepartum maternal factors and umbilical cord blood interleukin-6 (IL-6) data were analyzed. FIRS was defined as IL-6 > 11 pg/mL.

RESULTS

Umbilical cord blood IL-6 and maternal blood data within 24 h before parturition were available for 158 cases; 66 were diagnosed with FIRS (41.8%; median IL-6, 57.55 pg/mL). We created a risk score (FIRS score) comprising expected delivery weeks (≤30 weeks), maternal C-reactive protein (≥1.2 mg/dL), maternal white blood cell count (≥13 000/μL), corticosteroid use (none) and PROM latency period (≥3 days) from the multivariate logistic regression model predicting FIRS. Receiver operating characteristic curve analysis of the score produced the following results: area under the curve, 0.82; 95% CI, 0.76-0.89; cut-off value, 7.5; sensitivity, 89%; specificity, 63%; positive predictive value, 63% and negative predictive value, 89%. The probability of FIRS according to the categories of the FIRS score was 11% for those with a score of 0-7, 50% for a score of 8-15, and 88% for a score of 16-22.

CONCLUSION

The devised maternal risk score could predict FIRS and be helpful to decide the delivery timing for the cases of PPROM.

Semiquantitative Ultrasound Assessment of Lung Aeration Correlates With Lung Tissue Inflammation

We studied the relationship between ultrasound-assessed lung aeration and inflammation in a particular population of ventilated preterm neonates with mild-to-moderate lung inflammation and no congenital heart defect. Lung aeration estimated by a semiquantitative lung ultrasound score significantly correlated with several inflammatory markers both at cellular (neutrophil count in bronchoalveolar lavage: ρ = 0.400, p = 0.018) and molecular level (total proteins: ρ = 0.524, p = 0.021; interleukine-8: ρ = 0.523, p = 0.021; granulocytes-macrophages colony stimulating factor: ρ = 0.493, p = 0.020; all measured in bronchoalveolar lavage and expressed as epithelial lining fluid concentrations). Lung ultrasound might detect changes in lung aeration attributable to mild-to-moderate local inflammation if cardiogenic lung edema is excluded. Thus, it is possible to describe some levels of lung inflammation with semiquantitative lung ultrasound.

Histological chorioamnionitis is predicted by early infant C-reactive protein in preterm infants and correlates with neonatal outcomes

AIM

Histological chorioamnionitis (HCA) is associated with preterm birth and adverse neonatal outcomes. We evaluated the rise in C-reactive protein (CRP) in preterm infants as a predictor of HCA severity and outcomes.

METHODS

Consecutive preterm infants, born January 2009 to January 2014 in the National Maternity Hospital, Dublin, under 32 weeks' gestation or <1.5 kg birthweight, were included. Histological chorioamnionitis was staged as maternal inflammatory response, foetal inflammatory response and non-HCA.

RESULTS

Preterm infants (n = 518) were included with a mean gestational age 28.5 ± 2.8 weeks, birthweight 1.1 ± 0.3 kg, and 53.5% were male. Histological chorioamnionitis was found in 25.4%. Histological chorioamnionitis was present in 93.7% when CRP > 5 mg/L, 65.2% when CRP 1-5 mg/L and in 19.4% when CRP < 1 mg/L. When both the immature to total neutrophil (IT) ratio was >0.2 and the CRP > 1 mg/L the positive predictive value and negative predictive value for HCA were 92.5% and 84.9%, respectively. Histological chorioamnionitis was associated with more resuscitation and respiratory distress syndrome (both P < .001). A CRP > 10 mg/L was associated with a foetal inflammatory response and increased early-onset sepsis.

CONCLUSION

Higher early CRP was a surrogate predictor of HCA and correlated with the severity of HCA. Higher CRP and HCA were associated with adverse early outcomes.

A perfect storm: fetal inflammation and the developing immune system

Histologic chorioamnionitis is an inflammatory disorder of the placenta that commonly precedes preterm delivery. Preterm birth related to chorioamnionitis and fetal inflammation has been associated with a risk for serious inflammatory complications in infancy. In addition, preterm infants exposed to chorioamnionitis may be more susceptible to infection in the neonatal intensive care unit and possibly later in life. A significant body of work has established an association between chorioamnionitis and inflammatory processes. However, the potential consequences of this inflammation on postnatal immunity are less understood. In this review, we will discuss current knowledge regarding the effects of fetal exposure to inflammation on postnatal immune responses.

Pulmonary Consequences of Prenatal Inflammatory Exposures: Clinical Perspective and Review of Basic Immunological Mechanisms

Chorioamnionitis, a potentially serious inflammatory complication of pregnancy, is associated with the development of an inflammatory milieu within the amniotic fluid surrounding the developing fetus. When chorioamnionitis occurs, the fetal lung finds itself in the unique position of being constantly exposed to the consequent inflammatory meditators and/or microbial products found in the amniotic fluid. This exposure results in significant changes to the fetal lung, such as increased leukocyte infiltration, altered cytokine, and surfactant production, and diminished alveolarization. These alterations can have potentially lasting impacts on lung development and function. However, studies to date have only begun to elucidate the association between such inflammatory exposures and lifelong consequences such as lung dysfunction. In this review, we discuss the pathogenesis of and fetal immune response to chorioamnionitis, detail the consequences of chorioamnionitis exposure on the developing fetal lung, highlighting the various animal models that have contributed to our current understanding and discuss the importance of fetal exposures in regard to the development of chronic respiratory disease. Finally, we focus on the clinical, basic, and therapeutic challenges in fetal inflammatory injury to the lung, and propose next steps and future directions to improve our therapeutic understanding of this important perinatal stress.

Estimation of early life endogenous surfactant pool and CPAP failure in preterm neonates with RDS

Background

It is not known if the endogenous surfactant pool available early in life is associated with the RDS clinical course in preterm neonates treated with CPAP. We aim to clarify the clinical factors affecting surfactant pool in preterm neonates and study its association with CPAP failure.

Methods

Prospective, pragmatic, blind, cohort study. Gastric aspirates were obtained (within the first 6 h of life and before the first feeding) from 125 preterm neonates with RDS. Surfactant pool was measured by postnatal automated lamellar body count based on impedancemetry, without any pre-analytical treatment. A formal respiratory care protocol based on European guidelines was applied. Clinical data and perinatal risk factors influencing RDS severity or lamellar body count were real-time recorded. Investigators performing lamellar body count were blind to the clinical data and LBC was not used in clinical practice.

Results

Multivariate analysis showed gestational age to be the only factor significantly associated with lamellar body count (standardized β:0.233;p = 0.023). Lamellar body count was significantly higher in neonates with CPAP success (43.500 [23.750–93.750]bodies/μL), than in those failing CPAP (20.500 [12.250–49.750] bodies/μL;p = 0.0003).LBC had a moderate reliability to detect CPAP failure (AUC: 0.703 (0.615–0.781);p < 0.0001; best cut-off: ≤30,000 bodies/μL). Upon adjustment for possible confounders, neither lamellar body count, nor its interaction factor with gestational age resulted associated with CPAP failure.

Conclusions

Early postnatal lamellar body count on gastric aspirates in CPAP-treated preterm neonates with RDS is significantly influenced only by gestational age. Lamellar bodies are not associated with CPAP failure. Thus, the endogenous surfactant pool available early in life only has a moderate reliability to predict CPAP failure.

A Multicenter Lung Ultrasound Study on Transient Tachypnea of the Neonate

BACKGROUND AND AIM

Discordant results that demand clarification have been published on diagnostic lung ultrasound (LUS) signs of transient tachypnea of the neonate (TTN) in previous cross-sectional, single-center studies. This work was conducted to correlate clinical and imaging data in a longitudinal and multicenter fashion.

METHODS

Neonates with a gestational age of 34-40 weeks and presenting with TTN underwent a first LUS scan at 60-180 min of life. LUS scans were repeated every 6-12 h if signs of respiratory distress persisted. Images were qualitatively described and a LUS aeration score was calculated. Clinical data were collected during respiratory distress.

RESULTS

We enrolled 65 TTN patients. Thirty-one (47.6%) had a sharp echogenicity increase in the lower lung fields (the "double lung point" or DLP sign). On admission, there was no significant difference between patients with and without DLP in Silverman scores (4 ± 1.5 vs. 4 ± 2.1; p = 0.9) or LUS scores (7.6 ± 2.6 vs. 5.6 ± 3.8; p = 0.12); PaO2/FiO2 (249 ± 93 vs. 252 ± 125; p = 0.91). All initial LUS scans (performed at the onset of distress) and 99.5% of all scans showed a regular pleural line with no consolidation, with only 1 neonate showing consolidation in the follow-up scans. The Silverman and LUS scores were significantly correlated (rho = 0.27; p = 0.02).

CONCLUSION

A regular pleural line with no consolidation is a consistent finding in TTN. The presence of a DLP is not essential for the LUS diagnosis of TTN. A semi-quantitative LUS score correlates well with the clinical course and could be useful in monitoring changes in lung aeration during TTN.

Urinary metabolomic analysis to identify preterm neonates exposed to histological chorioamnionitis: A pilot study

OBJECTIVE

Chorioamnionitis is a leading cause of preterm birth worldwide, with higher incidence at lower gestational ages. An early and reliable diagnosis of histological chorioamnionitis (HCA) in preterm infants may be helpful in guiding postnatal management, especially the administration of prophylactic antibiotics to prevent early-onset sepsis. The main aim of this study was to investigate metabolomic analysis of urines collected in the first 24 hours of life as diagnostic tool of HCA.

METHODS

Gestational age-, birth weight-, delivery mode- and sex- matched (1:2) preterm neonates (< 35 weeks' gestation) born to mothers with or without HCA were enrolled from an observational study. Gas chromatography-mass spectrometry (GC-MS)-based metabolomic analysis was performed on urine samples non-invasively collected in the first 24 hours of life. Univariate analysis, partial least square discriminant analysis (PLS-DA) and its associated variable importance in projection (VIP) score were performed. The most affected metabolic pathways were examined by Metabolite Sets Enrichment Analysis (MSEA).

RESULTS

Fifteen cases (mean GA 30.2 ± 3.8 weeks, mean BW 1415 ± 471.9 grams) and 30 controls (mean GA 30.2 ± 2.9 weeks, mean BW 1426 ± 569.8 grams) were enrolled. Following univariate analysis, 29 metabolites had a significantly different concentration between cases and controls. The supervised PLS-DA model confirmed a separation between the two groups. Only gluconic acid, an oxidation product of glucose, was higher in cases than in controls. All other VIP metabolites were more abundant in the control group. Glutamate metabolism, mitochondrial electron transport chain, citric acid cycle, galactose metabolism, and fructose and mannose degradation metabolism were the most significantly altered pathways (P < 0.01).

CONCLUSIONS

For the first time, urinary metabolomics was able to discriminate neonates born to mothers with and without HCA. The identification of specifically altered metabolic pathways may be helpful in understanding metabolic derangement following chorioamnionitis.

Can the preterm lung recover from perinatal stress?

After birth, adequate lung function is necessary for the successful adaptation of a preterm baby. Both prenatal and postnatal insults and therapeutic interventions have an immediate effect on lung function and gas exchange but also interfere with fetal and neonatal lung development. Prenatal insults like chorioamnionitis and prenatal interventions like maternal glucocorticosteroids interact but might also determine the preterm baby's lung response to postnatal interventions ("second hit") like supplementation of oxygen and drug therapy. We review current experimental and clinical findings on the influence of different perinatal factors on preterm lung development and discuss how well-established interventions in neonatal care might be adapted to attenuate postnatal lung injury.

Automated auditory brainstem response in preterm newborns with histological chorioamnionitis

OBJECTIVE

We investigated whether histological chorioamnionitis is associated with an adverse neonatal hearing outcome.

METHODS

Two cohorts of very preterm newborns (n = 548, gestational age ≤ 32.0 weeks) were linked to placental histology and automated auditory brainstem response (AABR) outcome.

RESULTS

In multivariable analyses, an abnormal AABR was not predicted by the presence of histological chorioamnionitis, either with or without fetal involvement (OR 1.4, 95% CI 0.5 - 3.8, p = 0.54 and OR 1.1, 95% CI 0.4-3.0, p = 0.79, respectively). Significant predictors of abnormal AABR included, e.g. birth weight (per kg increase: OR 0.2, 95% CI 0.0-0.6, p = 0.006), umbilical cord artery pH (per 0.1 increase: OR 0.7, 95% CI 0.5-0.9, p = 0.005) and mechanical ventilation (OR 3.7, 95% CI 1.2-11.6, p = 0.03).

CONCLUSIONS

Histological chorioamnionitis was not associated with an adverse neonatal hearing outcome in two cohorts of very preterm newborns. Indicators of a complicated neonatal clinical course were the most important predictors of an abnormal hearing screening.

Outcomes of very-low-birth-weight infants exposed to maternal clinical chorioamnionitis: a multicentre study

BACKGROUND

Chorioamnionitis is a recognized risk factor of preterm delivery; however, controversy still persists concerning the relationship between maternal inflammation and neonatal morbidity and mortality.

OBJECTIVE

To determine the incidence of clinical chorioamnionitis and its relationship to morbidity and mortality among very-low-birth-weight (VLBW) infants.

METHODS

This was a retrospective analysis of prospectively collected data of VLBW neonates ≤ 32 weeks' gestational age (GA) admitted to collaborating units in the Spanish SEN1500 Network between January 2008 and December 2011. Clinical chorioamnionitis was defined by obstetricians based on clinical findings, and neonatal outcomes were compared between exposed and non-exposed infants by multivariate logistic regression analysis.

RESULTS

During the study period, 11,464 VLBW newborns were admitted to our units and 10,026 were ≤ 32 weeks' GA. Among them, 8,330 (83.1%) had complete data and were included. Of these, 1,480 (17.8%) were exposed to maternal clinical chorioamnionitis. The incidence was higher at lower GA and, after adjusting for confounding factors, exposed infants had higher risks of early-onset neonatal sepsis (EONS) (10.0 vs. 2.8%; aOR 3.102; 95% CI 2.306-4.173; p < 0.001) and necrotizing enterocolitis (NEC) (11.2 vs. 7.7%; aOR 1.300; 95% CI 1.021-1.655; p < 0.033), but lower risks of patent ductus arteriosus (PDA) (43.2 vs. 34.9%; aOR 0.831; 95% CI 0.711-0.971; p < 0.02) and late-onset bacterial sepsis (LONS) (36.6 vs. 32.5%; aOR 0.849; 95% CI 0.729-0.989; p < 0.035). There were no differences in mortality between the groups.

CONCLUSIONS

The incidence of maternal clinical chorioamnionitis is inversely related to GA at delivery, and in VLBW infants ≤ 32 weeks' GA it is associated with higher risks of EONS and NEC, but lower risks of PDA and LONS. We did not found differences in survival.