Universal cervical length screening and risk of spontaneous preterm birth: a systematic review and meta-analysis

OBJECTIVE

To evaluate the risk of spontaneous preterm birth with or without universal transvaginal ultrasound cervical length screening at the time of midtrimester scan.

DATA SOURCES

Medline, Embase, ClinicalTrials.gov, and Web of Science were systematically searched from the inception of the databases to November 12, 2023, using combinations of the relevant medical subject heading terms, key words, and word variants that were considered suitable for the topic.

STUDY ELIGIBILITY CRITERIA

Studies including individuals with singleton gestations at 16-25 weeks of gestation screened or not screened with universal transvaginal ultrasound cervical length screening were considered eligible. Primary outcome was spontaneous preterm birth <37 weeks; secondary outcomes were spontaneous preterm birth <34 and <32 weeks.

METHODS

Random effect head-to-head analyses were used to directly compare each outcome, expressing the results as summary odds ratio and relative 95% confidence interval. The quality of the included studies was independently assessed by 2 reviewers, using the Newcastle-Ottawa scale for cohort studies and the Cochrane risk-of-bias tool for randomized controlled studies. The study was registered on the prospective register of systematic reviews database (PROSPERO) (registration number: CRD42022385325).

RESULTS

Eight studies, including 447,864 pregnancies, were included in the meta-analysis (213,064 screened with transvaginal ultrasound cervical length and 234,800 unscreened). In the overall analysis, universal transvaginal ultrasound cervical length did not significantly decrease the spontaneous preterm birth rates <37 weeks (odds ratio, 0.92 [95% confidence interval, 0.84-1.01], P=.07) and <34 weeks (odds ratio, 0.87 [95% confidence interval, 0.73-1.04], P=.12), but was significantly associated with a lower risk of spontaneous preterm birth <32 weeks (odds ratio, 0.84 [95% confidence interval, 0.76-0.94], P=.002). Individuals without a prior spontaneous preterm birth had a significantly lower risk of spontaneous preterm birth <37 weeks (odds ratio, 0.88 [95% confidence interval, 0.79-0.97], P=.01) and a lower trend of spontaneous preterm birth <32 weeks (odds ratio, 0.82 [95% confidence interval, 0.66-1.01], P=.06) when screened with transvaginal ultrasound cervical length, compared with no screening.

CONCLUSION

Universal transvaginal ultrasound cervical length screening usually <24 weeks in singletons without a prior spontaneous preterm birth, is associated with a significant reduction in spontaneous preterm birth <37 weeks, compared with no screening.

Speculum-free portable preterm imaging system

Significance

Preterm birth is defined as a birth before 37 weeks of gestation and is one of the leading contributors to infant mortality rates globally. Premature birth can lead to life-long developmental impairment for the child. Unfortunately, there is a significant lack of tools to diagnose preterm birth risk, which limits patient care and the development of new therapies.

Aim

To develop a speculum-free, portable preterm imaging system (PPRIM) for cervical imaging; testing of the PPRIM system to resolve polarization properties of birefringent samples; and testing of the PPRIM under an IRB on healthy, non-pregnant volunteers for visualization and polarization analysis of cervical images.

Approach

The PPRIM can perform 4 × 3 Mueller-matrix imaging to characterize the remodeling of the uterine cervix during pregnancy. The PPRIM is built with a polarized imaging probe and a flexible insertable sheath made with a compatible flexible rubber-like material to maximize comfort and ease of use.

Results

The PPRIM device is developed to meet specific design specifications as a speculum-free, portable, and comfortable imaging system with polarized imaging capabilities. This system comprises a main imaging component and a flexible silicone inserter. The inserter is designed to maximize comfort and usability for the patient. The PPRIM shows high-resolution imaging capabilities at the 20 mm working distance and 25 mm circular field of view. The PPRIM demonstrates the ability to resolve birefringent sample orientation and full field capture of a healthy, non-pregnant cervix.

Conclusion

The development of the PPRIM aims to improve access to the standard of care for women's reproductive health using polarized Mueller-matrix imaging of the cervix and reduce infant and maternal mortality rates and better quality of life.

First-trimester and early-second-trimester transvaginal cervical length before 16 weeks among women with preterm and term birth: a systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the differences in first-trimester and early-second-trimester transvaginal cervical length between patients with spontaneous preterm birth and those with term birth.

DATA SOURCES

PubMed, MEDLINE, Embase, and the Cochrane Library were systematically searched through August 2023.

STUDY ELIGIBILITY CRITERIA

Studies had to include (1) transvaginal cervical length measurement before 16+0 weeks of gestation and (2) transvaginal cervical length measurement in a population of patients who delivered preterm and at term. Abstracts, studies with duplicated data, and those with cervical length measured by transabdominal ultrasound scan were excluded.

METHODS

K.W.C. and J.L. searched for, screened, and reviewed the articles independently. The quality of the studies was assessed using the Newcastle-Ottawa scale. Mean differences were calculated using a random-effects model and pooled through a meta-analysis.

RESULTS

A total of 5727 published articles were identified. Only 10 studies (which analyzed 22,151 pregnancies) met the inclusion criteria. All studies excluded iatrogenic preterm birth. Transvaginal cervical length was significantly shorter in women with spontaneous preterm birth than in those who delivered at term (mean difference, -0.97; 95% confidence interval, -1.65 to -0.29; P=.005; I2=69%). When a linear technique was used to measure transvaginal cervical length, a significantly shorter transvaginal cervical length was associated with spontaneous preterm birth as opposed to term birth (mean difference, -1.09; 95% confidence interval, -1.96 to -0.21; P=.02; I2=77%). A shorter transvaginal cervical length measured by other techniques was also associated with spontaneous preterm birth before 34 to 35 weeks (mean difference, -1.87; 95% confidence interval, -3.04 to -0.70; P=.002; I2=0%). When studies where interventions were given for a "short" cervix or studies with a mean transvaginal cervical length ≥40 mm were excluded, a significantly shorter transvaginal cervical length was observed among those with spontaneous preterm birth (mean difference, -1.13; 95% confidence interval, -1.89 to -0.37; P=.004; mean difference, -0.86; 95% confidence interval, -1.67 to -0.04; P=.04; respectively). The optimal transvaginal cervical length cutoff was 38 to 39 mm, yielding pooled sensitivity of 0.80, specificity of 0.45, positive likelihood ratio of 1.16, negative likelihood ratio of 0.33, diagnostic odds ratio of 5.12, and an area under the curve of 0.75.

CONCLUSION

Women with spontaneous preterm birth had significantly shorter transvaginal cervical length before 16 weeks of gestation compared with those who delivered at term. The linear method and the 2-line method are acceptable techniques for measuring transvaginal cervical length.

MicroRNA Associations with Preterm Labor-A Systematic Review

This systematic review delves into the connections between microRNAs and preterm labor, with a focus on identifying diagnostic and prognostic markers for this crucial pregnancy complication. Covering studies disseminated from 2018 to 2023, the review integrates discoveries from diverse pregnancy-related scenarios, encompassing gestational diabetes, hypertensive disorders and pregnancy loss. Through meticulous search strategies and rigorous quality assessments, 47 relevant studies were incorporated. The synthesis highlights the transformative potential of microRNAs as valuable diagnostic tools, offering promising avenues for early intervention. Notably, specific miRNAs demonstrate robust predictive capabilities. In conclusion, this comprehensive analysis lays the foundation for subsequent research, intervention strategies and improved outcomes in the realm of preterm labor.

Systemic lupus erythematosus is associated with an increased frequency of spontaneous preterm births: systematic review and meta-analysis

OBJECTIVE

Preterm birth is one of the most frequent complications of pregnancy in women with systemic lupus erythematosus. The high indicated preterm birth proportion due to hypertensive disorders of pregnancy and/or fetal growth restriction is well known, and preventive measures and screening for early detection are performed. The risk of spontaneous preterm birth is less well recognized. This study aimed to determine the proportions of spontaneous and indicated preterm birth in pregnancies of women with systemic lupus erythematosus.

DATA SOURCES

A systematic literature search using Pubmed, Embase, Web of Science, and Google Scholar was performed in June 2021.

STUDY ELIGIBILITY CRITERIA

Studies in pregnant women with systemic lupus erythematosus reporting spontaneous and indicated preterm birth rates were selected. Original research articles published from 1995 to June 2021 were included.

METHODS

Quality and risk of bias of the included studies were assessed using the Newcastle-Ottawa quality assessment scale. To estimate the pooled event rates and 95% confidence intervals, meta-analysis of single proportions with a random-effects model was performed.

RESULTS

We included 21 articles, containing data of 8157 pregnancies in women with systemic lupus erythematosus. On average, 31% (95% prediction interval, 0.14-0.50) of the pregnancies resulted in preterm birth, including 14% (95% prediction interval, 0.04-0.27) spontaneous and 16% (95% prediction interval, 0.03-0.35) indicated preterm birth.

CONCLUSION

In pregnant women with systemic lupus erythematosus, spontaneous and indicated preterm birth proportions are high. This information should be applied in (prepregnancy) counseling and management in pregnancy. The knowledge obtained by this meta-analysis paves the way for further research of associated risk factors and development of interventions to reduce spontaneous preterm birth in systemic lupus erythematosus pregnancies.

Parturition at term: induction, second and third stages of labor, and optimal management of life-threatening complications-hemorrhage, infection, and uterine rupture

Childbirth is a defining moment in anyone's life, and it occurs 140 million times per year. Largely a physiologic process, parturition does come with risks; one mother dies every two minutes. These deaths occur mostly among healthy women, and many are considered preventable. For each death, 20 to 30 mothers experience complications that compromise their short- and long-term health. The risk of birth extends to the newborn, and, in 2020, 2.4 million neonates died, 25% in the first day of life. Hence, intrapartum care is an important priority for society. The American Journal of Obstetrics & Gynecology has devoted two special Supplements in 2023 and 2024 to the clinical aspects of labor at term. This article describes the content of the Supplements and highlights new developments in the induction of labor (a comparison of methods, definition of failed induction, new pharmacologic agents), management of the second stage, the value of intrapartum sonography, new concepts on soft tissue dystocia, optimal care during the third stage, and common complications that account for maternal death, such as infection, hemorrhage, and uterine rupture. All articles are available to subscribers and non-subscribers and have supporting video content to enhance dissemination and improve intrapartum care. Our hope is that no mother suffers because of lack of information.

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.

Indomethacin Pharmacokinetics and Pharmacodynamics in Pregnancies With Preterm Labor: The Need for Dose-Ranging Trials

The use of indomethacin to delay delivery in preterm labor (PTL) is widely accepted; however, the optimal dosage of indomethacin in pregnancy is unknown. Here, we perform population pharmacokinetic (PK) and pharmacodynamic (PD) analyses, characterize the plasma disposition of indomethacin in pregnant women with PTL, and relate indomethacin exposure to delayed delivery and maternal/neonatal safety. We analyzed plasma and urine samples collected from a multicenter, prospective, opportunistic PK/PD study of indomethacin in pregnant women 12-32 weeks gestation admitted with PTL. Ninety-four participants with 639 plasma concentrations for indomethacin were included in the analysis. The final population PK (popPK) model for indomethacin was a 2-compartment structural model with first-order absorption and elimination and a covariate effect of body mass index on apparent oral clearance. We observed a 21%-60% increase in apparent oral clearance observed during pregnancy. There was no clear association between indomethacin exposure and maternal or neonatal safety outcomes, or with the magnitude of delayed delivery; however, 96.7% of women treated with indomethacin had a delivery that was delayed at least 48 hours. Given the changes to indomethacin apparent oral clearance during pregnancy, and the lack of relationship between indomethacin exposure and safety, dose-finding studies of indomethacin in pregnant women with PTL may help clarify the most safe and efficacious dosage and duration of indomethacin.

Bitter taste receptors in the reproductive system: Function and therapeutic implications

Type 2 taste receptors (TAS2Rs), traditionally known for their role in bitter taste perception, are present in diverse reproductive tissues of both sexes. This review explores our current understanding of TAS2R functions with a particular focus on reproductive health. In males, TAS2Rs are believed to play potential roles in processes such as sperm chemotaxis and male fertility. Genetic insights from mouse models and human polymorphism studies provide some evidence for their contribution to male infertility. In female reproduction, it is speculated that TAS2Rs influence the ovarian milieu, shaping the functions of granulosa and cumulus cells and their interactions with oocytes. In the uterus, TAS2Rs contribute to uterine relaxation and hold potential as therapeutic targets for preventing preterm birth. In the placenta, they are proposed to function as vigilant sentinels, responding to infection and potentially modulating mechanisms of fetal protection. In the cervix and vagina, their analogous functions to those in other extraoral tissues suggest a potential role in infection defense. In addition, TAS2Rs exhibit altered expression patterns that profoundly affect cancer cell proliferation and apoptosis in reproductive cancers. Notably, TAS2R agonists show promise in inducing apoptosis and overcoming chemoresistance in these malignancies. Despite these advances, challenges remain, including a lack of genetic and functional studies. The application of techniques such as single-cell RNA sequencing and clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated endonuclease 9 gene editing could provide deeper insights into TAS2Rs in reproduction, paving the way for novel therapeutic strategies for reproductive disorders.

Is Parity a Risk Factor for Late Preterm Birth? Results from a Large Cohort Study

Most preterm births occur in the late preterm period. While prematurity-related adverse outcomes are significantly diminished when birth occurs during this period, these infants are still at increased risk of complications. Parity affects the incidence of obstetric complications. The purpose of this study was to determine whether parity impacts the risk of spontaneous late preterm birth (SLPTB) and associated complications. A retrospective observational cohort study was conducted. Patients were divided into three study groups according to parity. The primary outcome was the rate of SLPTB in each group. Secondary outcomes were unplanned cesarean delivery (UCD), prolonged third stage of labor respiratory distress syndrome (RDS), transient tachypnea of the newborn (TTN), intraventricular hemorrhage (IVH), neonatal hypoglycemia, duration of NICU admission, neonatal death, and composite adverse neonatal outcome (CANO). Primiparas were more likely to have SLPTB, UCD, and CANO compared to multiparas (2.6% vs. 1.9% OR 1.5 [1.3-1.7] p < 0.01) (4.1% vs. 1.3% OR 2.7 [1.2, 5.9] p < 0.01) (8.5% vs. 4.2 OR 2.1 [1.3-3.5] p = 0.002) and grandmultiparas (2.6% vs. 1.7% OR 1.4 [1.2-1.5] p < 0.001) 8.5% vs. 4.4% OR 2.0 [1.1, 3.8], p = 0.01) but no difference in UCD compared to grandmultiparas (4.1% vs. 3.3% OR 1.2 [0.6-2.7] p = 0.28). Primiparas are at increased risk of SLPTB and UCD, and this is accompanied by an increased risk of adverse neonatal outcomes.

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.

Ambulation for latency during expectant management of preterm prelabor rupture of membranes: a randomized controlled trial (AMBLE)

BACKGROUND

Individuals hospitalized with preterm prelabor rupture of membranes are often advised to limit their activity or adhere to bed rest. Some evidence suggests that greater activity is associated with longer latency and improved outcomes, but no high-quality evidence from a randomized controlled trial exists.

OBJECTIVE

This study aimed to evaluate whether encouragement to ambulate at least 2000 steps daily affects latency among individuals with preterm prelabor rupture of membranes compared with usual care.

STUDY DESIGN

This was a multisite unblinded, 2-arm randomized trial of individuals at 23 0/7 to 35 0/7 weeks of gestation undergoing inpatient expectant management of preterm prelabor rupture of membranes with planned delivery at least 7 days away. Each participant wore a Fitbit Inspire that tracked steps. The intervention arm was encouraged (verbal and Fitbit-based reminders) to reach a goal of 2000 steps per day. The usual-care arm was allowed ad libitum activity with no step goal or reminders. The primary outcome was latency (days) from randomization to delivery. Secondary analyses included composite neonatal and maternal clinical outcomes and maternal mental health survey results. Statistical analyses were conducted with an intent-to-treat approach under a Bayesian framework using neutral priors (a priori assumed 50:50 likelihood of longer latency in either arm). A total of 100 participants were required to have 80% power to demonstrate a 4-day difference in latency with 75% certainty (Bayesian probability).

RESULTS

Among 163 eligible individuals, 100 (61%) were randomized, and after loss to follow-up, 95 were analyzed. Gestational age at randomization was 29 3/7 weeks (interquartile range, 26 2/7 to 31 5/7) in the intervention arm and 27 4/7 weeks (interquartile range, 25 4/7 to 29 6/7) in the usual-care arm. Median step counts were 1690 per day in the intervention arm (interquartile range, 1031-2641) and 1338 per day in the usual-care arm (interquartile range, 784-1913). Median days of latency were 9 days in the intervention arm (interquartile range, 4-17) and 6 days in the usual-care arm (interquartile range, 2-14). The primary analysis indicated a 65% posterior probability that the intervention increased latency relative to usual care (posterior relative risk, 1.09; 95% credible interval, 0.70-1.71). The relative risk was 0.55 (95% credible interval, 0.32-0.82) for the composite neonatal adverse outcome, with 99% posterior probability of intervention benefit, and was 0.94 (95% credible interval, 0.72-1.20) for the composite maternal adverse outcome, with 70% posterior probability of intervention benefit. There was a 94% posterior probability of the intervention arm having a greater decrease in maternal stress score from baseline to before delivery compared with the usual-care arm (mean arm difference, 3.24 points [95% credible interval, -7.23 to 0.79]). Adjustment for gestational age at randomization had minimal impact on secondary outcome results.

CONCLUSION

Individuals with preterm prelabor rupture of membranes randomized to encouragement to ambulate had a longer latency to delivery and improved neonatal and mental health outcomes, with similar maternal clinical outcomes compared with usual care.

Relationship Between Anatomic Features of the Placenta, the Type of Abnormal Placental Cord Insertion and Adverse Pregnancy Outcomes in Singleton Pregnancies: A Prospective Observational Study

INTRODUCTION

This study aimed to evaluate the potential value of placental anatomic features and various types of normal and abnormal cord insertion types in predicting adverse maternal-fetal outcomes in singleton pregnancies. We also tried to assess the association between these outcomes and various types of placental cord insertion.

METHOD

This prospective observational study was performed on singleton pregnancies. For each patient placental features including diameter, thickness, type of cord insertion, and the shortest distance between the cord insertion point and placental edge were recorded. The relationship between these factors and the development of multiple adverse pregnancy outcomes including preterm labor, intrauterine fetal death (IUFD), and the rate of neonatal intensive care unit (NICU) admissions were evaluated and reported.

RESULTS

Overall 308 patients were enrolled in the study. Smoker mothers had significantly smaller placentas (P-value = .008), and those with lower diameter placentas were more likely to suffer from IUFD (P-value = .0001). Shorter placental cord insertion distances led to more episodes of preterm labor (P-value = .057). Eccentric-type placental cord insertion was significantly associated with the development of preeclampsia (P-value = .006).

DISCUSSION

Abnormalities in placental diameter and cord insertion can lead to significant maternal-fetal complications including preterm labor, IUFD, and preeclampsia.

Preterm Birth: Screening and Prediction

Preterm birth (PTB) affects approximately 10% of births globally each year and is the most significant direct cause of neonatal death and of long-term disability worldwide. Early identification of women at high risk of PTB is important, given the availability of evidence-based, effective screening modalities, which facilitate decision-making on preventative strategies, particularly transvaginal sonographic cervical length (CL) measurement. There is growing evidence that combining CL with quantitative fetal fibronectin (qfFN) and maternal risk factors in the extensively peer-reviewed and validated QUanititative Innovation in Predicting Preterm birth (QUiPP) application can aid both the triage of patients who present as emergencies with symptoms of preterm labor and high-risk asymptomatic women attending PTB surveillance clinics. The QUiPP app risk of delivery thus supports shared decision-making with patients on the need for increased outpatient surveillance, in-patient treatment for preterm labor or simply reassurance for those unlikely to deliver preterm. Effective triage of patients at preterm gestations is an obstetric clinical priority as correctly timed administration of antenatal corticosteroids will maximise their neonatal benefits. This review explores the predictive capacity of existing predictive tests for PTB in both singleton and multiple pregnancies, including the QUiPP app v.2. and discusses promising new research areas, which aim to predict PTB through cervical stiffness and elastography measurements, metabolomics, extracellular vesicles and artificial intelligence.

The effect of genital hygiene behaviors and vaginal douching of pregnant women on preterm labor

OBJECTIVE

To determine the effect of genital hygiene behavior (GHB) and vaginal douching (VD) of pregnant women on preterm labor (PTL).

METHODS

This study, which was conducted with 365 pregnant women, is a cross-sectional study. Data were collected using a questionnaire and the Genital Hygiene Behavior Inventory (GHBI) was applied.

RESULTS

The ratios of PTL diagnosis and VD practice, and mean GHBI scores of the pregnant women were 35.1%, 9.6%, and 64.42 ± 10.44, respectively. The prevalence of receiving a diagnosis of PTL was significantly higher in those who changed their underwear two to three times a week, took baths while sitting, cleansed their perineum with water using their hands, removed pubic hair at intervals of 2 months or longer, and performed VD. It was found that poor GHB and VD practices increased the rate of PTL and, in particular, VD was found to increase the risk of PTL around eight-fold.

CONCLUSION

These results can help pregnant women to understand the relationship between genital hygiene and PTL and show the importance of being educated by health professionals about this issue.

Addressing a broken drug pipeline for preterm birth: why early preterm birth is an orphan disease

Preterm birth remains one of the most urgent unresolved medical problems in obstetrics, yet only 2 therapeutics for preventing preterm birth have ever been approved by the United States Food and Drug Administration, and neither remains on the market. The recent withdrawal of 17-hydroxyprogesterone caproate (17-OHPC, Makena) marks a new but familiar era for obstetrics with no Food and Drug Administration-approved pharmaceuticals to address preterm birth. The lack of pharmaceuticals reflects a broad and ineffective pipeline hindered by extensive regulatory hurdles, soaring costs of performing drug research, and concerns regarding adverse effects among a particularly vulnerable population. The pharmaceutical industry has historically limited investments in research for diseases with similarly small markets, such as cystic fibrosis, given their rarity and diminished projected financial return. The Orphan Drug Act, however, incentivizes drug development for "orphan diseases", defined as affecting <200,000 people in the United States annually. Although the total number of preterm births in the United States exceeds this threshold annually, the early subset of preterm birth (<34 weeks' gestation) would qualify, which is predominantly caused by inflammation and infection. The scientific rationale for classifying preterm birth into early and late subsets is strong given that their etiologies differ, and therapeutics that may be efficacious for one subset may not work for the other. For example, antiinflammatory therapeutics would be expected to be highly effective for early but not late preterm birth. A robust therapeutic pipeline of antiinflammatory drugs already exists, which could be used to target spontaneous early preterm birth, in combination with antibiotics shown to sterilize the amniotic cavity. New applications for therapeutics targeting spontaneous early preterm birth could categorize as orphan disease drugs, which could revitalize the preterm birth therapeutic pipeline. Herein, we describe why drugs targeting early preterm birth should qualify for orphan status, which may increase pharmaceutical interest for this vitally important obstetrical condition.

Rapid detection of bacteria and antimicrobial resistant genes in intraamniotic infection using nanopore adaptive sampling

Nanopore adaptive sampling to diagnose intraamniotic infection

Techniques for detecting cervical remodeling as a predictor for spontaneous preterm birth: current evidence and future research avenues in patients with multiple pregnancies

BACKGROUND

Spontaneous preterm birth occurs more frequently in multiple pregnancies. This syndrome has multiple triggers that result in a unified downstream pathway of cervical remodeling, uterine activity, and progressive cervical dilatation. Whilst the triggers for labor in multiple pregnancy may be different from singletons, the downstream changes will be the same. Identifying patients at risk of preterm birth is a priority as interventions to delay delivery and optimize the fetus can be initiated. Methods for screening for risk of preterm birth which focus on the detection of cervical remodeling may therefore have potential in this population.

METHODS

This review explores the evidence for the predictive utility for preterm birth of several published techniques that assess the physical, biomechanical, and optical properties of the cervix, with a focus on those which have been studied in multiple pregnancies and highlighting targets for future research in this population.

RESULTS

Fifteen techniques are discussed which assess the physical, biomechanical, and optical properties of the cervix in pregnancy. Of these, only three techniques that evaluated the predictive accuracy of a technique in patients with multiple pregnancies were identified: uterocervical angle, cervical consistency index, and cervical elastography. Of these, measurement of the uterocervical angle has the strongest evidence. Several techniques have shown predictive potential in singleton pregnancies, but have not yet been studied in multiple pregnancies, which would be a logical expansion of research.

CONCLUSION

Research on techniques with predictive utility for PTB in patients with multiple pregnancies is limited but should be a research priority. Overall, the theory supports the investigation of cervical remodeling as a predictor of PTB, and there are numerous techniques in development that may have potential in this field.

Randomized trial of advice from healthcare professionals to eliminate constriction by maternal clothing on the trunk to prevent preterm birth and improve health status

AIM

Women's clothing during pregnancy may influence perinatal outcomes. A preliminary study suggested that midwives' advice to avoid wearing tight clothing during pregnancy may reduce the risk of preterm delivery. We examined the effects of such advice to pregnant women on the risk of preterm birth and health status during pregnancy.

METHODS

An open-label evaluator-blinded randomized controlled trial was conducted at the National Centre for Child Health and Development in Tokyo, Japan. Normal pregnant women were randomly assigned to receive constrictive clothing elimination care or standard care at 20 weeks gestation. The control group was issued leaflets concerning anemia prevention at entry and skin care at 30 weeks' gestation, along with a brief explanation and answers to questions by midwives as standard care. The intervention group received advice from midwives concerning avoiding constrictive clothing in addition to standard care. The primary outcome was the incidence of preterm birth (<37 weeks). The secondary outcomes were 12 indicators related to preterm delivery or health status.

RESULTS

Among 624 randomly assigned women, 599 (intervention group, n = 306; control group, n = 293) completed the study between February 2015 and August 2016. The incidence of preterm birth in the intervention and control groups was 4.2% (13/306) and 5.1% (15/293), respectively (p = 0.614). There were no significant differences regarding any secondary outcomes, including obstetric outcomes and physical/mental indicators, during pregnancy.

CONCLUSIONS

Advice from midwives to avoid constrictive clothing during pregnancy did not influence the incidence of preterm birth or maternal health status.

TRIAL REGISTRATION

UMIN000016853 (March 30, 2015).

A prospective study of antepartum anxiety screening in patients with and without a history of spontaneous preterm birth

BACKGROUND

Maternal stress has been identified as one of the most common clinical phenotypes associated with preterm birth. The American College of Obstetricians and Gynecologists recommends anxiety screening at least once in the perinatal period. The prevalence of perinatal anxiety is challenged by the absence of formalized screening protocols and underreporting in high-risk populations, such as those with a history of adverse pregnancy outcomes.

OBJECTIVE

This study administered a validated anxiety screening tool in a cohort of patients with and without a previous spontaneous preterm birth and compared differences in score and rate of a positive screen between groups. Moreover, this study evaluated perinatal outcomes associated with a positive screen and described a referral protocol involving evaluation by a perinatal mental health counselor and clinical diagnoses. A hypothesis was made that patients with a previous history of spontaneous preterm birth would have higher self-reported anxiety symptoms than controls and that those with recurrent preterm delivery at <35 weeks of gestation would have the highest anxiety screening scores.

STUDY DESIGN

This was a prospective observational cohort study administering the Generalized Anxiety Disorder 7-item screen to patients enrolled in 2 prenatal care clinics at our institution. The preterm birth cohort consisted of patients with a history of spontaneous preterm labor, premature rupture of membranes, or cervical insufficiency compared with the control cohort without this history. Screening was initiated at entry to prenatal care or referral to our high-risk obstetrical clinic. The inclusion criteria included English- or Spanish-speaking patients and singleton pregnancy, and the exclusion criteria included pregnancies complicated by a major congenital anomaly, enrollment after 34 weeks of gestation, delivery at <20 weeks of gestation, and incomplete delivery data. Referral to a mental health counselor was offered to those with a Generalized Anxiety Disorder 7-item screen score of ≥10. Perinatal outcomes as a comparison between the Generalized Anxiety Disorder 7-item screen-positive group and Generalized Anxiety Disorder 7-item screen-negative group were performed with statistical methods, including the Student t test, chi-square test, and Wilcoxon rank-sum test, with a P value of <.05 to determine significance.

RESULTS

Between September 2020 and December 2021, 1349 participants were analyzed, with 143 patients (11%) in the previous preterm birth cohort and 1206 (89%) patients in the control cohort. Patients with a history of preterm birth and subsequent delivery at ≤35 weeks of gestation in the study pregnancy had significantly higher Generalized Anxiety Disorder 7-item screen scores than controls with delivery after 35 weeks of gestation (median score: 4 [interquartile range, 1-9] vs 2 [interquartile range, 0-6], respectively; P=.006). Overall, 187 participants (14%) screened positive with significantly higher rates in the previous preterm birth group than in the control group (20% vs 13%; P=.036). Of note, 117 patients (63%) accepted a referral, and 32 patients (17%) with a positive screen were diagnosed with a perinatal mood disorder.

CONCLUSION

Patients with recurrent preterm birth have higher self-reported anxiety using the Generalized Anxiety Disorder 7-item screen than controls. Of those with a positive screen, 17% were diagnosed with a perinatal mood disorder.

Use, misuse, and overuse of antenatal corticosteroids. A retrospective cohort study

OBJECTIVES

To evaluate the timing of antenatal corticosteroids (ACS) administration in relation to the delivery timing based on indications and risk factors for preterm delivery.

METHODS

We conducted a retrospective cohort study to understand what factors predict the optimal timing of ACS administration (ACS administration within seven days). We reviewed consecutive charts of adult pregnant women receiving ACS from January 1, 2011, to December 31, 2019. We excluded pregnancies under 23 weeks, incomplete and duplicate records, and patients delivered outside our health system. The timing of ACS administration was categorized as optimal or suboptimal. These groups were analyzed regarding demographics, indications for ACS administration, risk factors for preterm delivery, and signs and symptoms of preterm labor.

RESULTS

We identified 25,776 deliveries. ACS were administered to 531 pregnancies, of which 478 met the inclusion criteria. Of the 478 pregnancies included in the study, 266 (55.6 %) were delivered in the optimal timeframe. There was a higher proportion of patients receiving ACS for the indication of threatened preterm labor in the suboptimal group as compared to the optimal group (85.4 % vs. 63.5 %, p<0.001). In addition, patients who delivered in the suboptimal timeframe had a higher proportion of short cervix (33 % vs. 6.4 %, p<0.001) and positive fetal fibronectin (19.8 % vs. 1.1 %, p<0.001) compared to those who delivered in the optimal timeframe.

CONCLUSIONS

More emphasis should be placed on the judicious use of ACS. Emphasis should be placed on clinical assessment rather than relying solely on imaging and laboratory tests. Re-appraisal of institutional practices and thoughtful ACS administration based on the risk-benefit ratio is warranted.

Effects of Education and Guided Imagery Program on Stress Level and Coping Behaviors Among Pregnant Women at Risk of Preterm Birth

Purpose

The rate of preterm birth continues to increase worldwide. Pregnant women at risk of preterm birth experience more stress during pregnancy, which directly impacts their mental well-being and preterm birth situation. Stress management can significantly reduce stress and promote appropriate coping behaviors in pregnant women at risk of preterm birth. The purpose of this study was to determine the effects of education and guided imagery program on stress level and coping behaviors among pregnant women at risk of preterm birth.

Patients and Methods

Forty-eight pregnant women who visited the antenatal care unit at Ramathibodi Hospital and were at risk of preterm birth with moderate stress score were included. They were divided into two groups, each comprising 24 participants. The control group received standard nursing care, whereas the experimental group received an education and guided imagery program in addition to standard nursing care. The Perceived Stress Scale-10 and Coping Behavior Questionnaire were used to collect data.

Results

The results revealed that the mean stress score in the experimental group after receiving the program was lower than before with statistical significance (t = 7.14, p < 0.001). Moreover, the experimental group had lower stress score (F1,45 = 16.92, p < 0.001) and greater coping behavior score (F1,45 = 7.85, p < 0.01) compared with the control group after receiving the program, and the differences were statistically significant.

Conclusion

This research highlights the importance of preventing mental health problems in pregnant women at risk of preterm birth by using an education and guided imagery program to decrease stress and promote appropriate coping behaviors.

FIGO good practice recommendations for preterm labor and preterm prelabor rupture of membranes: Prep-for-Labor triage to minimize risks and maximize favorable outcomes

Preterm labor occurs in around 10% of pregnancies worldwide. Once diagnosed, significant efforts must be made to reduce the likelihood of morbidity and mortality associated with preterm birth. In high-resource settings, access to hospitals with a neonatal intensive care unit (NICU) is readily available, whereas access to NICU care is limited in low- and middle-income countries (LMICs) and many rural settings. Use of FIGO's Prep-for-Labor triage method rapidly identifies low- and high-risk patients with preterm labor to enable clinicians to decide whether the patient can be managed on site or if transfer to a level II-IV facility is needed. The management steps described in this paper aim to minimize the morbidity and mortality associated with preterm labor and in the setting of preterm labor with preterm premature rupture of membranes (PPROM). The methods for accurate diagnosis of PPROM and chorioamnionitis are described. When the risk of preterm birth is high, antenatal corticosteroids should be administered for lung maturation combined with limited tocolysis for 48 hours to permit the corticosteroid course to be completed. Magnesium sulfate is also administered for fetal neuroprotection. Implementation of FIGO's Prep-for-Labor triage method in an LMIC setting will help improve maternal and neonatal outcomes.

Inflammasomes in human reproductive diseases

Inflammasomes are multi-protein complexes localized within immune and non-immune cells that induce caspase activation, proinflammatory cytokine secretion, and ultimately pyroptosis-a type of cell death. Inflammasomes are involved in a variety of human diseases, especially acute or chronic inflammatory diseases. In this review, we focused on the strong correlation between the NLRP3 inflammasome and various reproductive diseases, including ovarian aging or premature ovarian insufficiency, PCOS, endometriosis, recurrent spontaneous abortion, preterm labor, pre-eclampsia, and male subfertility, as well as the multifaceted role of NLRP3 in the pathogenesis and treatment of these diseases. In addition, we provide an overview of the structure and amplification of inflammasomes. This comprehensive review demonstrates the vital role of NLRP3 inflammasome activation in human reproductive diseases together with the underlying mechanisms, offers new insights for mechanistic studies of reproduction, and provides promising possibilities for the development of drugs targeting the NLRP3 inflammasome for the treatment of reproductive disorders in the future.

Pathophysiological Implications of Interstitial Cajal-like Cells (ICC-like) in Uterus: A Comparative Study with Gastrointestinal ICCs

The main function of interstitial cells of Cajal (ICCs) is to regulate gastrointestinal peristalsis by acting as a "pacemaker" cell by generating spontaneous slow electrical waves. In 2005, electron microscopy revealed a cell type similar to ICCs (ICC-like) outside the gastrointestinal tract, with contractile activity and c-Kit+ immunohistochemistry shared with ICCs. Among the locations where ICC-like cells have been observed, it is in the uterus where they have a significant functional and pathophysiological role. These cells are involved in obstetric phenomena of contractile action, such as ascending sperm transport, embryo implantation, pregnancy, delivery, and the expulsion of menstrual debris. Within the pathophysiology related to these cells, we find obstetric alterations such as recurrent miscarriages, premature deliveries, abolition of uterine contractions, and failures of embryo implantation, in addition to other common conditions in the fertile age, such as endometriosis and leiomyoma.

Benefits of Premaquick® Combined Detection of IL-6/Total IGFBP-1/Native IGFBP-1 to Predict Preterm Delivery

We conducted a prospective double-blind study to compare two vaginal diagnostic methods in singleton pregnancies with threatened preterm labor (TPL) at the University Hospital of Clermont-Ferrand (France) from August 2018 to December 2020. Our main objective was to compare the diagnostic capacity at admission, in terms of positive predictive value (PPV) and negative predictive value (NPV), of Premaquick® (combined detection of IL-6/total IGFBP-1/native IGFBP-1) and QuikCheck fFN™ (fetal fibronectin) for delivery within 7 days in cases of TPL. We included 193 patients. Premaquick® had a sensitivity close to 89%, equivalent to QuikCheck fFN™, but a higher statistical specificity of 49.5% against 38.6% for QuikCheck fFN™. We found no superiority of Premaquick® over QuickCheck fFN™ in terms of PPV (6.6% vs. 7.9%), with NPV being equivalent in predicting childbirth within 7 days in cases of TPL (98.6% vs. 98.9%). Nevertheless, the combination of positive native and total IGFBP-1 and the combination of all three positive markers were associated with a higher PPV. Our results, though non-significant, support this combined multiple-biomarker approach to improve testing in terms of predictive values.

Association of clinical signs of chorioamnionitis with histological chorioamnionitis and neonatal outcomes in women with premature rupture of membranes

Background

Premature rupture of membrane (PROM), especially when preterm or prolonged is associated with an increased risk of chorioamnionitis with its attendant feto-maternal complications.

Aim

The study was aimed to determine the association of clinical signs of chorioamnionitis with histological chorioamnionitis and neonatal outcomes in women with PROM.

Materials and Methods

Eligible participants with clinical diagnosis of PROM at gestational age of ≥28 weeks managed between December 2018 and June 2019 were consecutively recruited. Their sociodemographic characteristics, obstetrics history, and evidence of clinical chorioamnionitis using the Gibb's criteria were obtained. Following delivery, chorioamnionitis was histologically confirmed. Primary outcome measure was the proportion of women with PROM and histological chorioamnionitis that were detected clinically.

Results

Of the 136 participants analyzed, 108 (79.4%) had term PROM, while 28 (20.6%) had preterm PROM (<37 weeks). The prevalence of histological chorioamnionitis was 50.0% compared to 16.2% using clinical indicators of infection. Histological chorioamnionitis was almost two times higher in preterm than term PROM (71.4% vs 38.9%). About two-third (67.6%) of the chorioamnionitis identified histologically were missed using clinical signs of chorioamnionitis. Clinical signs of chorioamnionitis had specificity of 100.0%, but low sensitivity (35.5%) and accuracy of 70.6%. A combination of three symptoms, maternal pyrexia and tachycardia, and fetal tachycardia appears to be the most reliable clinical indicator of chorioamnionitis in women with preterm PROM. There was a significant association between low birth weight, low Apgar score, NICU admission, and the presence of histological chorioamnionitis in women that had PROM.

Conclusion

Clinical signs of chorioamnionitis have a low sensitivity and are not very accuracy in diagnosing chorioamnionitis in women with PROM.

Investigating the predictive role of uterocervical angle in predicting preterm labor in singleton pregnancies: a meta-analysis

OBJECTIVES

In this meta-analysis, we aimedto demonstrate the relationship between uterocervical angle and preterm labor in singleton pregnancies more clearly and reliablywith this meta-analysis.

MATERIAL AND METODS

In this study, we use keywords such as "uterocervical angle," "cervical angle," "angle," "cervix," "cervical," "preterm," and "preterm labour." We searched various databases, including PubMed, MEDLINE, ClinicalKey, Scopus, ScienceDirect, Web of Science, and Google Scholar. The search encompassed the period from January 1, 2010, to December 27, 2020. As a result of the literature review, a total of 585 articles were identified. After the screening and selection process, six studies met the inclusion criteria and were included in the analysis. These six studies were deemed relevant and provided valuable information on the research topic.

RESULTS

When the Egger test (p = 0.020) and Begg test (p = 0.188) were performed, no significant publication bias was found in the studies examined. These statistical tests assess publication bias, and the resulting p-values indicate a low probability of bias in the included studies. Cochran's Q test revealed the presence of heterogeneity among the included studies. Heterogeneity indicates variability in the results beyond what would be expected by chance alone. This finding suggests that the studies may differ in methodologies, populations, or other factors, which could impact the overall results and require further investigation. There was a significant difference between the patient and control groups (p < 0.001). This result provides strong evidence to support the importance of the difference between the two groups compared.

CONCLUSIONS

Based on the findings of this study, a wider uterocervical angle appeared to be significantly associated with an increased risk of preterm delivery in overall effect. It concluded that a wide uterocervical angle may be a potential risk factor for preterm delivery. Moreover, the study revealed a significant association between wider uterocervical angles and an elevated risk of preterm labour in singleton pregnancies. In this study, the definition of preterm birth accepts as birth before 37 weeks of gestation. These results highlight the potential significance of evaluating the uterocervical angle as a meaningful predictor for identifying the propensity of preterm labour in singleton pregnancies.

Hypoxia-inducible factor 1 signaling drives placental aging and can provoke preterm labor

Most cases of preterm labor have unknown cause, and the burden of preterm birth is immense. Placental aging has been proposed to promote labor onset, but specific mechanisms remain elusive. We report findings stemming from unbiased transcriptomic analysis of mouse placenta, which revealed that hypoxia-inducible factor 1 (HIF-1) stabilization is a hallmark of advanced gestational timepoints, accompanied by mitochondrial dysregulation and cellular senescence; we detected similar effects in aging human placenta. In parallel in primary mouse trophoblasts and human choriocarcinoma cells, we modeled HIF-1 induction and demonstrated resultant mitochondrial dysfunction and cellular senescence. Transcriptomic analysis revealed that HIF-1 stabilization recapitulated gene signatures observed in aged placenta. Further, conditioned media from trophoblasts following HIF-1 induction promoted contractility in immortalized uterine myocytes, suggesting a mechanism by which the aging placenta may drive the transition from uterine quiescence to contractility at the onset of labor. Finally, pharmacological induction of HIF-1 via intraperitoneal administration of dimethyloxalyl glycine (DMOG) to pregnant mice caused preterm labor. These results provide clear evidence for placental aging in normal pregnancy, and demonstrate how HIF-1 signaling in late gestation may be a causal determinant of the mitochondrial dysfunction and senescence observed within the trophoblast as well as a trigger for uterine contraction.

Extracellular matrix-related and serine protease proteins in the amniotic fluid of women with early preterm labor: Association with spontaneous preterm birth, intra-amniotic inflammation, and microbial invasion of the amniotic cavity

PROBLEM

We aimed to determine whether altered levels of various extracellular matrix (ECM)-related and serine protease proteins in the amniotic fluid (AF) are associated with imminent spontaneous preterm birth (SPTB; ≤7 days) and intra-amniotic inflammation and/or microbial invasion of the amniotic cavity (IAI/MIAC) in women with early preterm labor (PTL).

METHOD OF STUDY

This retrospective cohort study included 252 women with singleton pregnancies undergoing transabdominal amniocentesis who demonstrated PTL (24-31 weeks). The AF was cultured for microorganism detection to characterize MIAC. IL-6 concentrations were determined in the AF samples to identify IAI (≥2.6 ng/mL). The following mediators were measured in the AF samples using ELISA: kallistatin, lumican, MMP-2, SPARC, TGFBI, and uPA.

RESULTS

Kallistatin, MMP-2, TGFBI, and uPA levels were significantly higher and SPARC and lumican levels were significantly lower in the AF of women who spontaneously delivered within 7 days than in the AF of those who delivered after 7 days; the levels of the first five mediators were independent of baseline clinical variables. In the multivariate analysis, elevated levels of kallistatin, MMP-2, TGFBI, and uPA and low levels of lumican and SPARC in the AF were significantly associated with IAI/MIAC and MIAC, even after adjusting for the gestational age at sampling. The areas under the curves of the aforementioned biomarkers ranged from 0.58 to 0.87 for the diagnoses of each of the corresponding endpoints.

CONCLUSION

ECM-related (SPARC, TGFBI, lumican, and MMP-2) and serine protease (kallistatin and uPA) proteins in the AF are involved in preterm parturition and regulation of intra-amniotic inflammatory/infectious responses in PTL.

Study Based on the Alliance Between Serum Magnesium Levels and Preterm Labor: An Inclusive Review

Preterm labor, regarded as the onset of labor before 37 weeks of gestation, is a highly prevalent issue in obstetrics with repercussions for neonatal health. This review article presents an in-depth analysis of the alliance between serum magnesium levels and preterm labor. The review explores the physiological roles of magnesium right through pregnancy, including its significance for energy metabolism, smooth muscle contraction, deoxyribonucleic acid (DNA), and protein synthesis. It addresses cellular transport and the homeostasis of magnesium. The pathophysiological processes encompassing inflammation, oxidative stress, calcium regulation, smooth muscle contractility, and neuroendocrine pathways are investigated. The review evaluates epidemiological studies investigating the alliance between serum magnesium levels and preterm labor. The review incorporates an assortment of study varieties, such as observational studies, case-control studies, prospective cohort studies, and meta-analyses. In the course of reviewing the prognostic relevance of serum magnesium levels in premature labor, therapeutic implications involving diagnostic precision, prognostic significance, and therapeutic response assessment have additionally been addressed. Therapeutic interventions targeting magnesium levels, such as magnesium supplementation, tocolytic therapy, and the role of magnesium in antenatal corticosteroid administration, are explored. This review provides an in-depth evaluation of the correlation between serum magnesium levels and preterm labor, stressing its therapeutic significance and repercussions for future research and treatment strategies.

Effect of Steroids on the Biophysical Profile and Doppler Indices of Umbilical and Middle Cerebral Arteries in Preterm Fetuses

Introduction Preterm birth is a major cause of perinatal death and disability and emerges as an important global public health problem. The antenatal administration of corticosteroids for preventing neonatal death due to respiratory distress syndrome and the serious morbidities associated with preterm birth has become an accepted standard in worldwide obstetric practice since 1994. After administering corticosteroids, the biophysical score deteriorates transiently, leading to a high cesarean section rate. Thus, Doppler indices of the umbilical and middle cerebral arteries are taken into account before the termination of pregnancy in preterm labor. Materials and methods This is an interventional study conducted over a period of one year and six months among 59 eligible singleton pregnancies at risk for preterm delivery, i.e., at risk of preterm birth <34 weeks of gestation, having no contraindication to antenatal steroids, who were admitted to the labor room of the Srirama Chandra Bhanja (SCB) Medical College, Cuttack, India, from January 2014 to August 2015. The participants were prospectively recruited, after giving informed consent to participate in the study. The main indication for hospital admission and steroid use was preterm lower abdominal pain. Results Out of 59 eligible cases, 27 (45.8%) were <25 years of age, 26 (44.1%) were between 25 and 30 years of age, and six (10.2%) were >30 years of age. The range is 14 years (between 19 and 33 years). The mean age is 25.31 years, with a standard deviation of 3.74. The mean of the biophysical profile (BPP) score before steroid administration decreased from 9.19 ± 1.23 to 5.56 ± 1.05 after 48 hours of first dose of steroid. The p-value of this is <0.001, which is statistically significant. The results show that the administration of betamethasone decreased fetal movements by 78.6% and breathing by 71.8%. As a result, the BPP scores decreased significantly. However, the Doppler indices did not change significantly even after administering corticosteroids. Conclusion Doppler indices play an important role in differentiating between steroid-induced compromise in the fetus and real fetal distress. Thus, umbilical and middle cerebral artery (MCA) Doppler should always be done before the termination of pregnancy on the ground of fetal compromise after administering corticosteroids.

Rescue doses of antenatal corticosteroids, children's neurodevelopment, and salivary cortisol after a threatened preterm labor: a 30-month follow-up study

BACKGROUND

Antenatal corticosteroids reduce neonatal complications when administered to women at risk for preterm birth. Moreover, antenatal corticosteroid rescue doses are recommended for women who remain at risk after the initial course. However, there is controversy about the most appropriate frequency and the exact timing of administering additional antenatal corticosteroid doses because there are potential long-term negative effects on infants' neurodevelopment and physiological stress functioning.

OBJECTIVE

This study aimed to (1) to assess the long-term neurodevelopmental effects of receiving antenatal corticosteroid rescue doses in comparison with receiving only the initial course; (2) to measure the cortisol levels of infants of mothers who received antenatal corticosteroid rescue doses; (3) to examine a potential dose-response effect of the number of antenatal corticosteroid rescue doses on children's neurodevelopment and salivary cortisol.

STUDY DESIGN

This study followed 110 mother-infant pairs who underwent a spontaneous episode of threatened preterm labor until the children were 30 months old, regardless of their gestational age at birth. Among the participants, 61 received only the initial course of corticosteroids (no rescue dose group), and 49 participants required at least one rescue dose of corticosteroids (rescue doses group). The follow-up was carried out at 3 different times, namely at threatened preterm labor diagnosis (T1), when the children were 6 months of age (T2), and when the children were 30 months of corrected age for prematurity (T3). Neurodevelopment was assessed using the Ages & Stages Questionnaires, Third Edition. Saliva samples were collected for cortisol level determination.

RESULTS

First, the rescue doses group showed lower problem-solving skills at 30 months of age than the no rescue doses group. Second, the rescue doses group demonstrated higher salivary cortisol levels at 30 months of age. Third, a dose-response effect was found that indicated that the more rescue doses the rescue doses group received, the lower the problem-solving skills and the higher the salivary cortisol levels at 30 months of age.

CONCLUSION

Our findings reinforce the hypothesis that additional antenatal corticosteroid doses provided after the initial course may have long-term effects on the neurodevelopment and glucocorticoid metabolism of the offspring. In this regard, the results raise concerns about the negative effects of repeated doses of antenatal corticosteroids in addition to a full course. Further studies are necessary to confirm this hypothesis to help physicians reassess the standard antenatal corticosteroid treatment regimens.

Maternal Plasma Lipid Profile and Risk of Spontaneous Preterm Labor Study in a Sample of Iranian Women in 2019

Background

Neonatal problems and adverse outcomes may be minimized by up to 90-75% when preterm delivery is diagnosed early and managed properly. This study aimed to determine the association of maternal plasma lipid indices with the occurrence of spontaneous preterm labor.

Material and Methods

This matched pair case-control study was performed on 80 pregnant women referred to a teaching hospital in Tehran for childbirth in 2019. The lipid profile was assessed in women with spontaneous preterm labor and term birth. According to age, Body Mass Index (BMI), pregnancy number, employment status, and educational level, the women in each group were paired. Data were analyzed using an independent-samples t-test, Mann-Whitney U-test, Chi-square, linear regression, and conditional logistic regression.

Results

Mean serum levels of total cholesterol, triglycerides, and low-density lipoprotein were all significantly higher in the case group compared with the control group (p < 0.05). The conditional logistic regression test confirmed that this association remained significant even after adjusting the effect of potentially confounding factors such as maternal age and body mass index. In addition, in linear regression the increased levels of triglyceride, total cholesterol, and low-density lipoprotein were found to be associated with 3.33-fold (1.32.-5.32 95% CI, p < 0.001), 2.94-fold (1.60-3.14 95% CI, p = 0.002), and 2.46-fold (1.31.-2.91 95% CI, p = 0.006) increased risk of preterm labor, respectively.

Conclusions

High triglyceride, total cholesterol, and low-density lipoprotein serum levels may be linked to an increased chance of spontaneous preterm labor, which might be considered a risk factor for this pregnancy problem.

Mirroring Perinatal Outcomes in a Romanian Adolescent Cohort of Pregnant Women from 2015 to 2021

Although the rates of adolescent pregnancies appear to have dropped according to the World Health Organization (WHO), the decrease in the age of the first menarche and better nutrition seems to contribute to the otherwise high rate of adolescent pregnancy worldwide, despite the efforts of different organizations to improve upon this trend. We conducted a population-based retrospective cohort study from January 2015 to December 2021 using our hospitals' database. We totaled 2.954 adolescent and 6.802 adult pregnancies. First, we compared younger adolescents' outcomes with those of older adolescents, as well as with adolescents aged between 18 and 19 years old; secondly, we compared adolescent pregnancies with adult ones. We detected higher percentages of cephalo-pelvic disproportion (43.2%), cervical dystocia (20.7%), and twin pregnancy (2.7%) in underage adolescents compared with 32%, 14.1%, and 1% in older underage adolescents, respectively, and 15.3%, 3.1%, and 0.6% in older ones. As teens became older, the likelihood of malpresentations and previous C-sections rose, whereas the likelihood of vaginal lacerations declined. When comparing adolescents with adult women, we found more cases that required episiotomy (48.1% compared with 34.6%), instrumental delivery (2.1% compared with 1%), and cervical laceration (10.7% compared with 8.4%) in the adolescent group, but the rates of malpresentation (11.4% compared with 13.5%), previous C-section (13.9% compared with 17.7%), and placenta and vasa praevia (4.5.6% compared with 14%) were higher in the adult women group. Adolescent pregnancy is prone to being associated with higher risks and complications and continues to represent a challenge for our medical system.

Prediction of Preterm Labor from the Electrohysterogram Signals Based on Different Gestational Weeks

Timely preterm labor prediction plays an important role for increasing the chance of neonate survival, the mother's mental health, and reducing financial burdens imposed on the family. The objective of this study is to propose a method for the reliable prediction of preterm labor from the electrohysterogram (EHG) signals based on different pregnancy weeks. In this paper, EHG signals recorded from 300 subjects were split into 2 groups: (I) those with preterm and term labor EHG data that were recorded prior to the 26th week of pregnancy (referred to as the PE-TE group), and (II) those with preterm and term labor EHG data that were recorded after the 26th week of pregnancy (referred to as the PL-TL group). After decomposing each EHG signal into four intrinsic mode functions (IMFs) by empirical mode decomposition (EMD), several linear and nonlinear features were extracted. Then, a self-adaptive synthetic over-sampling method was used to balance the feature vector for each group. Finally, a feature selection method was performed and the prominent ones were fed to different classifiers for discriminating between term and preterm labor. For both groups, the AdaBoost classifier achieved the best results with a mean accuracy, sensitivity, specificity, and area under the curve (AUC) of 95%, 92%, 97%, and 0.99 for the PE-TE group and a mean accuracy, sensitivity, specificity, and AUC of 93%, 90%, 94%, and 0.98 for the PL-TL group. The similarity between the obtained results indicates the feasibility of the proposed method for the prediction of preterm labor based on different pregnancy weeks.

β3 Receptor Signaling in Pregnant Human Myometrium Suggests a Role for β3 Agonists as Tocolytics

Preterm labor leading to preterm birth is the leading cause of infant morbidity and mortality. At the present time, nothing can reliably halt labor once it begins. The knowledge that agonists of the β2 adrenergic receptor relax airway smooth muscle and are effective in the treatment of asthma led to the notion that β2 mimetics would prevent preterm birth by relaxing uterine smooth muscle. The activation of cAMP-dependent protein kinase by β2 receptors is unable to provide meaningful tocolysis. The failure of β2 agonists such as ritodrine and terbutaline to prevent preterm birth suggests that the regulation of uterine smooth muscle is disparate from that of airway. Other smooth muscle quiescent-mediating molecules, such as nitric oxide, relax vascular smooth muscle in a cGMP-protein kinase G-dependent manner; however, nitric oxide activation of protein kinase G fails to explain the relaxation of the myometrium to nitric oxide. Moreover, nitric oxide-mediated relaxation is blunted in preterm labor, and thus, for this reason and because of the fall in maternal blood pressure, nitric oxide cannot be employed as a tocolytic. The β3 adrenergic receptor-mediated relaxation of the human myometrium is claimed to be cAMP-dependent protein kinase-dependent. This is scientifically displeasing given the failure of β2 agonists as tocolytics and suggests a non-canonical signaling role for β3AR in myometrium. The addition of the β3 agonist mirabegron to pregnant human myometrial strips in the tissue bath relaxes oxytocin-induced contractions. Mirabegron stimulates nitric oxide production in myometrial microvascular endothelial cells, and the relaxation of uterine tissue in vitro is partially blocked by the addition of the endothelial nitric oxide synthase blocker Nω-Nitro-L-arginine. Recent data suggest that both endothelial and smooth muscle cells respond to β3 stimulation and contribute to relaxation through disparate signaling pathways. The repurposing of approved medications such as mirabegron (Mybetriq™) tested in human myometrium as uterine tocolytics can advance the prevention of preterm birth.

Immunomodulatory role of decidual prolactin on the human fetal membranes and placenta

The close interaction between fetal and maternal cells during pregnancy requires multiple immune-endocrine mechanisms to provide the fetus with a tolerogenic environment and protection against any infectious challenge. The fetal membranes and placenta create a hyperprolactinemic milieu in which prolactin (PRL) synthesized by the maternal decidua is transported through the amnion-chorion and accumulated into the amniotic cavity, where the fetus is bedded in high concentrations during pregnancy. PRL is a pleiotropic immune-neuroendocrine hormone with multiple immunomodulatory functions mainly related to reproduction. However, the biological role of PRL at the maternal-fetal interface has yet to be fully elucidated. In this review, we have summarized the current information on the multiple effects of PRL, focusing on its immunological effects and biological significance for the immune privilege of the maternal-fetal interface.

Using Fetal Fibronectin Test to Reduce Hospital Admissions with Diagnosis of Preterm Labor: An Economic Evaluation Study

Background: Preterm labor and delivery remain a major problem in obstetrics accounting for perinatal morbidity and mortality. The challenge is to identify those with true preterm labor to avoid unnecessary hospital admissions. The fetal fibronectin (FFN) test is a strong predictor of preterm birth and can help identify women with true preterm labor. However, its cost-effectiveness as a strategy for triaging women with threatened preterm labor is still debatable. Objective: To evaluate the effect of FFN test implementation on hospital resources by reducing the admission rate of threatened preterm labor in a tertiary hospital, Latifa Hospital, UAE. Methods: A retrospective cohort study of singleton pregnancies between 24 and 34 weeks of gestation who attended Latifa Hospital in the period of September 2015-December 2016, complaining of threatened preterm labor after the availability of an FFN test, and a historical cohort study for those who attended with threatened preterm labor before the availability of an FFN test. Data analysis was performed using a Kruskal-Wallis test, Kaplan-Meier, Fischer exact chi-square and cost analysis. The significance was set at p-value < 0.05. Results: In total, 840 women met the inclusion criteria and were enrolled. The relative risk of FFN for delivery at term was 4.35 times higher among the negative-tested compared to preterm delivery (p-value < 0.001). A total of 134 (15.9%) women were unnecessarily admitted (FFN tested negative, delivered at term) which yielded $107,000 in extra costs. After the introduction of an FFN test, a 7% reduction of threatened preterm labor admissions was recorded.

The increased cfRNA of TNFSF4 in peripheral blood at late gestation and preterm labor: its implication as a noninvasive biomarker for premature delivery

Introduction

Given the important roles of immune tolerance and inflammation in both preterm and term labor, some inflammation-related genes could be related to the initiation of labor, even preterm labor. Inspection of cell-free RNA (cfRNA) engaged in inflammation in maternal blood may represent the varied gestational age and may have significant implications for the development of noninvasive diagnostics for preterm birth.

Methods

To identify potential biomarkers of preterm birth, we investigated the cfRNA and exosomal miRNA in the peripheral blood of pregnant women at different gestational ages that undergo term labor or preterm labor. 17 inflammatory initiation-related cfRNAs were screened by overlapping with the targets of decreasing miRNAs during gestation and highly expressed cfRNAs at late gestation in maternal blood. To reveal the origins and mechanisms of these screened cfRNAs, the datasets of single-cell RNA sequencing from peripheral blood mononuclear cells of pregnant women, the fetal lung, and the placenta across different gestational ages were analyzed.

Results

During late gestation, TNFSF4 expression increased exclusively in pro-inflammatory macrophages of maternal blood, whereas its receptor, TNFRSF4, increased expression in T cells from the decidua, which suggested the potential cell-cell communication of maternally-originated pro-inflammatory macrophages with the decidual T cells and contributed to the initiation of labor. Additionally, the cfRNA of TNFSF4 was also increased in preterm labor compared to term labor in the validation cohorts. The EIF2AK2 and TLR4 transcripts were increased in pro-inflammatory macrophages from both fetal lung and placenta but not in those from maternal mononuclear cells at late gestation, suggesting these cfRNAs are possibly derived from fetal tissues exclusively. Moreover, EIF2AK2 and TLR4 transcripts were found highly expressed in the pro-inflammatory macrophages from decidua as well, which suggested these specific fetal-origin macrophages may function at the maternal-fetal interface to stimulate uterine contractions, which have been implicated as the trigger of parturition and preterm labor.

Discussion

Taken together, our findings not only revealed the potential of peripheral TNFSF4 as a novel cfRNA biomarker for noninvasive testing of preterm labor but further illustrated how maternal and fetal signals coordinately modulate the inflammatory process at the maternal-fetal interface, causing the initiation of term or preterm labor.

Prevention and Therapy of Preterm Birth. Guideline of the DGGG, OEGGG and SGGG (S2k Level, AWMF Registry Number 015/025, September 2022) - Part 2 with Recommendations on the Tertiary Prevention of Preterm Birth and on the Management of Preterm Premature Rupture of Membranes

Aim The revision of this guideline was coordinated by the German Society for Gynecology and Obstetrics (DGGG), the Austrian Society for Gynecology and Obstetrics (OEGGG) and the Swiss Society for Gynecology and Obstetrics (SGGG). The aim of the guideline is to improve the prediction, prevention and management of preterm birth based on evidence from the current literature, the experience of members of the guidelines commission, and the viewpoint of self-help organizations. Methods The members of the contributing professional societies and organizations developed recommendations and statements based on international literature. The recommendations and statements were presented and adopted using a formal process (structured consensus conferences with neutral moderation, written Delphi vote). Recommendations Part 2 of this short version of the guideline presents statements and recommendations on the tertiary prevention of preterm birth and the management of preterm premature rupture of membranes.

Prevention and Therapy of Preterm Birth. Guideline of the DGGG, OEGGG and SGGG (S2k-Level, AWMF Registry Number 015/025, September 2022) - Part 1 with Recommendations on the Epidemiology, Etiology, Prediction, Primary and Secondary Prevention of Preterm Birth

Aim This revised guideline was coordinated by the German Society for Gynecology and Obstetrics (DGGG), the Austrian Society for Gynecology and Obstetrics (OEGGG) and the Swiss Society for Gynecology and Obstetrics (SGGG). It aims to improve the prediction, prevention, and management of preterm birth, based on evidence from the current literature, the experience of members of the guidelines commission, and the viewpoint of self-help organizations. Methods The members of the contributing professional societies and organizations developed recommendations and statements based on international literature. The recommendations and statements were presented and adopted using a formal process (structured consensus conferences with neutral moderation, written Delphi vote). Recommendations Part 1 of this short version of the guideline presents statements and recommendations on the epidemiology, etiology, prediction, and primary and secondary prevention of preterm birth.

Urinary oxidative stress biomarkers are associated with preterm birth: an Environmental Influences on Child Health Outcomes program study

BACKGROUND

Preterm birth is the leading cause of infant morbidity and mortality worldwide. Elevated levels of oxidative stress have been associated with an increased risk of delivering before term. However, most studies testing this hypothesis have been conducted in racially and demographically homogenous study populations, which do not reflect the diversity within the United States.

OBJECTIVE

We leveraged 4 cohorts participating in the Environmental Influences on Child Health Outcomes Program to conduct the largest study to date examining biomarkers of oxidative stress and preterm birth (N=1916). Furthermore, we hypothesized that elevated oxidative stress would be associated with higher odds of preterm birth, particularly preterm birth of spontaneous origin.

STUDY DESIGN

This study was a pooled analysis and meta-analysis of 4 birth cohorts spanning multiple geographic regions in the mainland United States and Puerto Rico (208 preterm births and 1708 full-term births). Of note, 8-iso-prostaglandin-F2α, 2,3-dinor-5,6-dihydro-8-iso-prostaglandin-F2α (F2-IsoP-M; the major 8-iso-prostaglandin-F2α metabolite), and prostaglandin-F2α were measured in urine samples obtained during the second and third trimesters of pregnancy. Logistic regression was used to calculate adjusted odds ratios and 95% confidence intervals for the associations between averaged biomarker concentrations for each participant and all preterm births, spontaneous preterm births, nonspontaneous preterm births (births of medically indicated or unknown origin), and categories of preterm birth (early, moderate, and late). Individual oxidative stress biomarkers were examined in separate models.

RESULTS

Approximately 11% of our analytical sample was born before term. Relative to full-term births, an interquartile range increase in averaged concentrations of F2-IsoP-M was associated with higher odds of all preterm births (odds ratio, 1.29; 95% confidence interval, 1.11-1.51), with a stronger association observed for spontaneous preterm birth (odds ratio, 1.47; 95% confidence interval, 1.16-1.90). An interquartile range increase in averaged concentrations of 8-iso-prostaglandin-F2α was similarly associated with higher odds of all preterm births (odds ratio, 1.19; 95% confidence interval, 0.94-1.50). The results from our meta-analysis were similar to those from the pooled combined cohort analysis.

CONCLUSION

Here, oxidative stress, as measured by 8-iso-prostaglandin-F2α, F2-IsoP-M, and prostaglandin-F2α in urine, was associated with increased odds of preterm birth, particularly preterm birth of spontaneous origin and delivery before 34 completed weeks of gestation.

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.

Peripartum management of deep venous thrombosis in the context of antithrombin deficiency and May-Thurner syndrome

Literature regarding the management of thrombus refractory to first-line treatment in the setting of pregnancy is limited, and management is made even more complicated in the context of thrombophilia. This case reviews the management of a patient with antithrombin deficiency who developed a massive thrombus during pregnancy, which was complicated by May-Thurner syndrome, lack of improvement with heparin, and preterm labor. The patient received multidisciplinary care throughout the pregnancy. At 35 weeks, anticoagulation was paused as she underwent induction of labor and delivery followed by postpartum placement of inferior vena cava filter and restarting heparin. Successful management of our pregnant patient with thrombus refractory to heparin hinged on individualized treatment for medical optimization with anticoagulation and antithrombin concentrate prior to labor followed by immediate postpartum placement of inferior vena cava filter.

Current Status and Prospects of the Single-Cell Sequencing Technologies for Revealing the Pathogenesis of Pregnancy-Associated Disorders

Single-cell RNA sequencing (scRNA-seq) is a method that focuses on the analysis of gene expression profile in individual cells. This method has been successfully applied to answer the challenging questions of the pathogenesis of multifactorial diseases and open up new possibilities in the prognosis and prevention of reproductive diseases. In this article, we have reviewed the application of scRNA-seq to the analysis of the various cell types and their gene expression changes in normal pregnancy and pregnancy complications. The main principle, advantages, and limitations of single-cell technologies and data analysis methods are described. We discuss the possibilities of using the scRNA-seq method for solving the fundamental and applied tasks related to various pregnancy-associated disorders. Finally, we provide an overview of the scRNA-seq findings for the common pregnancy-associated conditions, such as hyperglycemia in pregnancy, recurrent pregnancy loss, preterm labor, polycystic ovary syndrome, and pre-eclampsia.

Declaration of emergency state due to COVID-19 spread in Japan reduced maternal transports without reduction in preterm delivery

INTRODUCTION

To clarify whether the declaration of an emergency state due to the spread of COVID-19 in Japan affected the number of maternal transports and premature births.

METHODS

A questionnaire-based descriptive study was conducted in perinatal centers throughout Japan in 2020. The incidence of maternal transport and preterm delivery rates every month after the COVID-19 spread in 2020 were compared with those in 2019.

RESULTS

Participants were recruited from 52 perinatal centres. The maternal transport rate (maternal transports per number of deliveries) was 10.6% in April and 11.0% in June 2020, compared with 12.5% in 2019 (P < 0.05). The maternal transport rate due to preterm labor was 4.8% in April 2020 and 5.8% in 2019 (P < 0.05). The maternal transport rate during the declaration of emergency state decreased by 21% in April 2020 in non-emergency-declared prefectures, and decreased by 17% in May 2020 in emergency-declared prefectures. However, there was no significant difference in the preterm delivery rate between 2020 and 2019, regardless of the prefecture and gestational period.

CONCLUSION

Declaration of the emergency status due to COVID-19 spread in Japan reduced maternal transport due to preterm labor, but did not reduce preterm delivery itself.

Circumvention of luteolysis reveals parturition pathways in mice dependent upon innate type 2 immunity

Although mice normally enter labor when their ovaries stop producing progesterone (luteolysis), parturition can also be triggered in this species through uterus-intrinsic pathways potentially analogous to the ones that trigger parturition in humans. Such pathways, however, remain largely undefined in both species. Here, we report that mice deficient in innate type 2 immunity experienced profound parturition delays when manipulated endocrinologically to circumvent luteolysis, thus obliging them to enter labor through uterus-intrinsic pathways. We found that these pathways were in part driven by the alarmin IL-33 produced by uterine interstitial fibroblasts. We also implicated important roles for uterine group 2 innate lymphoid cells, which demonstrated IL-33-dependent activation prior to labor onset, and eosinophils, which displayed evidence of elevated turnover in the prepartum uterus. These findings reveal a role for innate type 2 immunity in controlling the timing of labor onset through a cascade potentially relevant to human parturition.

Cervical length screening for predicting preterm birth: A comparative review of guidelines

A cervical length (CL) assessment may predict preterm birth (PTB). This study aimed to analyze and compare the recommendations of guidelines on the role of CL in the prediction of PTB. There is no consensus regarding universal screening of asymptomatic women without a history of prior spontaneous PTB (sPTB), using CL. On the other hand, CL assessment is recommended in cases with a history of sPTB due to the high recurrence rate. Finally, there is discrepancy regarding CL assessment in asymptomatic women with multiple pregnancy. Although far from perfect, CL measurement remains the best available method to predict PTB.

Preterm labor with and without chorioamnionitis is associated with activation of myometrial inflammatory networks: a comprehensive transcriptomic analysis

BACKGROUND

The onset of preterm labor is associated with inflammation. Previous studies suggested that this is distinct from the inflammation observed during term labor. Our previous work on 44 genes differentially expressed in myometria in term labor demonstrated a different pattern of gene expression from that observed in preterm laboring and nonlaboring myometria. We found increased expression of inflammatory genes in preterm labor associated with chorioamnionitis, but in the absence of chorioamnionitis observed no difference in gene expression in preterm myometria regardless of laboring status, suggesting that preterm labor is associated with different myometrial genes or signals originating from outside the myometrium. Given that a small subset of genes were assessed, this study aimed to use RNA sequencing and bioinformatics to assess the myometrial transcriptome during preterm labor in the presence and absence of chorioamnionitis.

OBJECTIVE

This study aimed to comprehensively determine protein-coding transcriptomic differences between preterm nonlaboring and preterm laboring myometria with and without chorioamnionitis.

STUDY DESIGN

Myometria were collected at cesarean delivery from preterm patients not in labor (n=16) and preterm patients in labor with chorioamnionitis (n=8) or without chorioamnionitis (n=6). Extracted RNA from myometrial tissue was prepared and sequenced using Illumina NovaSeq. Gene expression was quantified by mapping the sequence reads to the human reference genome (hg38). Differential gene expression analysis, gene set enrichment analysis, and weighted gene coexpression network analysis were used to comprehensively interrogate transcriptomic differences and their associated biology.

RESULTS

Differential gene expression analysis comparing preterm patients in labor with chorioamnionitis with preterm patients not in labor identified 931 differentially expressed genes, whereas comparing preterm patients in labor without chorioamnionitis with preterm patients not in labor identified no statistically significant gene expression changes. In contrast, gene set enrichment analysis and weighted gene coexpression network analysis demonstrated that preterm labor with and without chorioamnionitis was associated with enrichment of pathways involved in activation of the innate immune system and inflammation, and activation of G protein-coupled receptors. Key genes identified included chemotactic CYP4F3, CXCL8, DOCK2, and IRF1 in preterm labor with chorioamnionitis and CYP4F3, FCAR, CHUK, and IL13RA2 in preterm labor without chorioamnionitis. There was marked overlap in the pathways enriched in both preterm labor subtypes.

CONCLUSION

Differential gene expression analysis demonstrated that myometria from preterm patients in labor without chorioamnionitis and preterm patients not in labor were transcriptionally similar, whereas the presence of chorioamnionitis was associated with marked gene changes. In contrast, comprehensive bioinformatic analysis indicated that preterm labor with or without chorioamnionitis was associated with innate immune activation. All causes of preterm labor were associated with activation of the innate immune system, but this was more marked in the presence of chorioamnionitis. These data suggest that anti-inflammatory therapy may be relevant in managing preterm labor of all etiologies.