High first trimester ferritin levels differ according to parity and are independently related to preterm birth: A prospective cohort study

INTRODUCTION

A considerable amount of neonatal morbidity and mortality worldwide is caused by preterm birth. To date, the underlying etiology of preterm birth has not been fully clarified. Previous studies demonstrate that inflammation is one of the pathological factors that might cause preterm birth, and that there is a difference between primiparous and multiparous women in immune response to pregnancy. The objective of this prospective cohort study was to investigate the role of two inflammatory markers, ferritin and C-reactive protein (CRP) and preterm birth, in first trimester women, stratified for parity. In addition, a possible association between high ferritin and CRP, and a possible association between high ferritin and CRP and preterm birth were assessed.

MATERIAL AND METHODS

A total of 2044 healthy, low-risk pregnant women from primary obstetric care in the Netherlands participated in this study. Their ferritin and CRP levels were evaluated at 12 weeks' gestation. Levels above the parity specific 95th percentile were defined as high. The main outcome of this study was to assess the presence of a possible association between parity specific high ferritin and CRP, and preterm birth. The secondary outcomes were the ferritin and CRP levels of women, stratified for parity, and the possible association between high ferritin and CRP levels. Logistic regression analysis was performed with preterm birth as a dependent variable and parity specific high ferritin and CRP as an independent variable, adjusting for age and history of preterm birth.

RESULTS

Ferritin levels decreased with increasing parity. Ferritin and CRP levels at 12 weeks' gestation were significantly higher in women with preterm birth. In primiparous women, high ferritin levels (OR: 2.5, CI: 1.14-5.38) and high CRP levels (OR: 5.0, CI: 2.61-9.94) were independently associated with preterm birth. In multiparous women, high ferritin levels (OR: 6.0, CI: 2.28-16.67) were independently associated with preterm birth while high CRP levels were not.

CONCLUSIONS

First trimester parity specific ferritin and CRP levels could play a part in predictive models for preterm birth, and further research for their additive role in preterm birth is needed.

Comparison of Four Tests for Preterm Birth Prediction in Symptomatic Singleton Women: A Prospective Cohort Study

Background and Purpose: It is challenging to predict preterm births accurately. We sought to compare the diagnostic performance of cervical length in predicting preterm birth to those of contraction recording in cardiotocography (CTG), cervical funneling, and Bishop score. Methods: A total of 371 women with singleton pregnancies and threatened preterm labor admitted to tertiary hospitals of northwestern Iran were included in this prospective cohort study and followed up until childbirth. Transvaginal ultrasound was utilized to assess the cervical length and funneling. Also, a CTG test and digital vaginal examination were performed. The data of 218 women were analyzed in the STATA software. The sensitivity and other diagnostic performances, and 95% confidence intervals, were reported. Results: The CTG uterine contraction recording had the highest sensitivity for predicting birth within the next 2 days, whereas a Bishop score ≥6 revealed the highest specificity, positive predictive value, and positive likelihood ratio. Inadequate cervical length for gestational age exhibited a high negative predictive value and the lowest negative likelihood ratio. Conclusion: The cervical length test has good diagnostic and prognostic performance among the four tests for preterm birth. Cervical funneling and CTG tests have poor predictive value, whereas the Bishop score has a superior diagnostic performance to the other tests.

Low-dose aspirin for the prevention of preterm birth in nulliparous women: systematic review and meta-analysis

OBJECTIVE

The objective was to assess the efficacy and safety of low-dose aspirin for the prevention of preterm birth in nulliparous women.

DATA SOURCES

We searched PubMed, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to June 2022.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials that compared aspirin to placebo in nulliparous women were eligible.

METHODS

This study was reported in accordance with the PRISMA 2020 checklist. The primary outcomes of this study were the rates of preterm birth at less than 37 weeks and less than 34 weeks of gestation. The secondary outcomes included postpartum hemorrhage, placental abruption, cesarean section, any hypertensive disorder of pregnancy and small for gestational age. Relative risks with their 95% confidence intervals were calculated for analysis. Heterogeneity was assessed by Cochran's Q test and Higgins's I2. A random-effects model was used when I2 was > 50% to generate the RR and 95% CI; otherwise, a fixed-effects model was used. The risk of publication bias was assessed by funnel plots. We performed sensitivity analysis by sequentially omitting each included study to confirm the robustness of the analysis.

RESULTS

Seven studies with a total of 29,029 participants were included in this review. Six studies were assessed as having a low risk of bias or an unclear risk of bias, and one study was judged as having a high risk of bias. In nulliparous women, low-dose aspirin was associated with a significant reduction in the rate of preterm birth at less than 34 weeks of gestational age (RR 0.84,95% CI: 0.71-0.99; I2 = 0%; P = 0.04), but we did not observe a significant difference in the rate of preterm birth at less than 37 weeks of gestation (RR 0.96,95% CI: 0.90-1.02; I2 = 31%; P = 0.18). Low-dose aspirin was associated with a significant increase in the rates of postpartum hemorrhage (RR 1.32,95% CI: 1.14-1.54; I2 = 0%; P = 0.0003), placental abruption (RR 2.18,95% CI: 1.10-4.32; I2 = 16%; P = 0.02) and cesarean section (RR 1.053, 95% CI: 1.001-1.108; I2 = 0%; P = 0.05) in nulliparous women. We also did not observe a significant effect of low-dose aspirin on the rates of any hypertensive disorder of pregnancy (RR 1.05, 95% CI: 0.96-1.14; I2 = 9%; P = 0.28) or small for gestational age (RR 0.96, 95% CI: 0.91-1.02; I2 = 0%; P = 0.16) in nulliparous women. Funnel plots indicated that no significant publication bias existed in this meta-analysis. Except for preterm birth at less than 34 weeks of gestation, placental abruption and cesarean section, the sensitivity analysis showed similar results, which confirmed the robustness of this meta-analysis.

CONCLUSIONS

Low-dose aspirin might reduce the risk of preterm birth at less than 34 weeks of gestation in nulliparous women. The use of low-dose aspirin in nulliparous women increased the risk of postpartum hemorrhage and might increase the risk of placental abruption and cesarean section.

Characterization of exosomal microRNAs in preterm infants fed with breast milk and infant formula

Breastfeeding not only reduces infection-related morbidity, but also increases growth of preterm infants. Advantages of breast milk (BM) for preterm infants are significant. They continue to be studied. However, because not all preterm infants can receive breastfeeding, bovine-based infant formula (IF) is used as an alternative, which may increase the risk of several preterm complications. Exosomes isolated from biofluids are emerging as biomarkers in research of various diseases. Here, we characterized miRNA contents of exosomes in urine and serum samples of preterm infants who were BM and IF fed and performed transcriptomic analysis of small RNA libraries. We identified significantly up-regulated 6 miRNAs and 10 miRNAs, respectively. Gene Ontology (GO) analysis revealed that target genes of these miRNAs might participate in neuronal development, immunity modulation, detoxification of reactive oxygen species, and transmembrane exchange. Our data suggest that exosome-based systemic screening for preterm infants with breastfeeding might be a screening tool for identifying target molecules involved in therapy for preterm infants in neonatal intensive care unit (NICU) and for future application as nutraceutical formulations or pharmaceuticals.

Exploring myometrial microenvironment changes at the single-cell level from nonpregnant to term pregnant states

The microenvironment and cell populations within the myometrium play crucial roles in maintaining uterine structural integrity and protecting the fetus during pregnancy. However, the specific changes occurring at the single-cell level in the human myometrium between nonpregnant (NP) and term pregnant (TP) states remain unexplored. In this study, we used single-cell RNA sequencing (scRNA-Seq) and spatial transcriptomics (ST) to construct a transcriptomic atlas of individual cells in the myometrium of NP and TP women. Integrated analysis of scRNA-Seq and ST data revealed spatially distinct transcriptional characteristics and examined cell-to-cell communication patterns based on ligand-receptor interactions. We identified and categorized 87,845 high-quality individual cells into 12 populations from scRNA-Seq data of 12 human myometrium tissues. Our findings demonstrated alterations in the proportions of five subpopulations of smooth muscle cells in TP. Moreover, an increase in monocytic cells, particularly M2 macrophages, was observed in TP myometrium samples, suggesting their involvement in the anti-inflammatory response. This study provides unprecedented single-cell resolution of the NP and TP myometrium, offering new insights into myometrial remodeling during pregnancy.NEW & NOTEWORTHY Using single-cell RNA sequencing and spatial transcriptomics, the myometrium was examined at the single-cell level during pregnancy. We identified spatially distinct cell populations and observed alterations in smooth muscle cells and increased M2 macrophages in term pregnant women. These findings offer unprecedented insights into myometrial remodeling and the anti-inflammatory response during pregnancy. The study advances our understanding of pregnancy-related myometrial changes.

Mode of Delivery and Neonatal Outcomes of Preterm Deliveries: A Retrospective Study in Greece

Background and Objectives: Preterm birth is a significant concern in obstetrics and neonatology since preterm neonates are at higher risk of various health complications and may require specialized care. The optimal mode of delivery in preterm birth is a matter of debate. This study aimed to evaluate the mode of delivery in preterm neonates and the associated neonatal outcomes. Material and Methods: This was a retrospective cohort study including all preterm neonates born between January 2010 and December 2020 at the 3rd Department of Obstetrics & Gynecology of Aristotle University of Thessaloniki, Greece. The mode of delivery in relation to gestational age groups and the cause of preterm birth were analyzed. Neonatal outcomes were also evaluated according to gestational age, indication and mode of delivery. Results: A total of 1167 preterm neonates were included in the study; the majority of them were delivered via cesarean section (76.1%). Most of the preterm neonates (n = 715; 61.3%) were delivered at 32+0-36+6 weeks, while cesarean section was the most common mode of delivery after 28+0 weeks. Furthermore, spontaneous onset of labor (OR: 6.038; 95% CI: 3.163-11.527; p < 0.001), multiple gestation (OR: 1.782; 95% CI: 1.165-2.227; p = 0.008) and fetal distress (OR: 5.326; 95% CI: 2.796-10.144; p < 0.001) were the main causes of preterm delivery at 32+0-36+6 weeks. The overall mortality rate was 8.1% among premature neonates. Regarding morbidity, 919 (78.7%) neonates were diagnosed with respiratory disorders, 129 (11.1%) with intraventricular hemorrhage and 30 (2.6%) with necrotizing enterocolitis. Early gestational age at delivery was the main risk factor of neonatal morbidity and mortality. Notably, the mode of delivery did not have any impact on neonatal survival (OR: 1.317; 95% CI: 0.759-2.284; p = 0.328), but preterm neonates born via cesarean section were at higher risk of respiratory disorders, compared to those born via vaginal delivery (OR: 2.208; 95% CI: 1.574-3.097; p < 0.001). Conclusions: Most preterm deliveries occurred in the moderate-to-late preterm period via cesarean section. Early gestational age at delivery was the main prognostic factor of neonatal morbidity and mortality, while the mode of delivery did not have any impact on neonatal survival. Future research on the mode of delivery of the preterm neonates is warranted to establish definitive answers for each particular gestational age.

Deciphering a critical role of uterine epithelial SHP2 in parturition initiation at single cell resolution

The timely onset of female parturition is a critical determinant for pregnancy success. The highly heterogenous maternal decidua has been increasingly recognized as a vital factor in setting the timing of labor. Despite the cell type specific roles in parturition, the role of the uterine epithelium in the decidua remains poorly understood. This study uncovers the critical role of epithelial SHP2 in parturition initiation via COX1 and COX2 derived PGF2α leveraging epithelial specific Shp2 knockout mice, whose disruption contributes to delayed parturition initiation, dystocia and fetal deaths. Additionally, we also show that there are distinct types of epithelium in the decidua approaching parturition at single cell resolution accompanied with profound epithelium reformation via proliferation. Meanwhile, the epithelium maintains the microenvironment by communicating with stromal cells and macrophages. The epithelial microenvironment is maintained by a close interaction among epithelial, stromal and macrophage cells of uterine stromal cells. In brief, this study provides a previously unappreciated role of the epithelium in parturition preparation and sheds lights on the prevention of preterm birth.

Risk Factors of Preterm Delivery in the Lao PDR: Hospital-Based Matched Case-Control Study

OBJECTIVE

To describe the risk factors among mothers in four central hospitals and two provincial hospitals in the Lao PDR, a lower-middle-income country in Southeast Asia.

METHOD

The study used a hospital-based matched case-control design study. Purposive sampling was used to select 320 mothers (80 cases and 240 controls) from the six hospitals. Cases were mothers who had delivered a live newborn between 28 and 36 weeks and 6 days, while controls were mothers who had delivered a live newborn within 37 and 40 weeks. Data were collected through a review of medical records and face-to-face interviews using a structured questionnaire. Data were entered into EPI info (Version 3.1) then exported to the STATA programme (Version 14) for univariate and conditional multiple logistic regressions to identify risk factors for PTD at p ≤ 0.05.

RESULTS

The mean maternal age of cases and controls was 25.2 (SD = 5.33) and 25.8 (SD = 4.37), respectively. In the multivariate analysis, factors with statistically significant relationships with PTD were the mother's religion (AOR: 3.01; 95% CI 1.24-7.26), the number of antenatal care visits (AOR: 3.39; 95% CI 1.6-7.18), having a pre-pregnancy maternal weight of less than 45 kg (AOR: 3.05; 95% CI 1.66-10.5), having had a premature preterm rupture of the membrane (AOR: 7.13; 95% CI 2.44-20.8) and vaginal bleeding during pregnancy (AOR: 6.89; 95% CI 3.02-15.73).

CONCLUSIONS FOR PRACTICE

Improving capacity of the Laotian health system to provide quality ANC and increasing the number of ANC contacts is critical. This requires context specific strategies that also address the socio-economic factors, such as access to a nutritious diet, that contribute to PTD.

Interpretable machine learning to predict adverse perinatal outcomes: examining marginal predictive value of risk factors during pregnancy

BACKGROUND

The timely identification of nulliparas at high risk of adverse fetal and neonatal outcomes during pregnancy is crucial for initiating clinical interventions to prevent perinatal complications. Although machine learning methods have been applied to predict preterm birth and other pregnancy complications, many models do not provide explanations of their predictions, limiting the clinical use of the model.

OBJECTIVE

This study aimed to develop interpretable prediction models for a composite adverse perinatal outcome (stillbirth, neonatal death, estimated Combined Apgar score of <10, or preterm birth) at different points in time during the pregnancy and to evaluate the marginal predictive value of individual predictors in the context of a machine learning model.

STUDY DESIGN

This was a secondary analysis of the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be data, a prospective cohort study in which 10,038 nulliparous pregnant individuals with singleton pregnancies were enrolled. Here, interpretable prediction models were developed using L1-regularized logistic regression for adverse perinatal outcomes using data available at 3 study visits during the pregnancy (visit 1: 6 0/7 to 13 6/7 weeks of gestation; visit 2: 16 0/7 to 21 6/7 weeks of gestation; visit 3: 22 0/7 to 29 6/7 weeks of gestation). We identified the important predictors for each model using SHapley Additive exPlanations, a model-agnostic method of computing explanations of model predictions, and evaluated the marginal predictive value of each predictor using the DeLong test.

RESULTS

Our interpretable machine learning model had an area under the receiver operating characteristic curves of 0.617 (95% confidence interval, 0.595-0.639; all predictor variables at visit 1), 0.652 (95% confidence interval, 0.631-0.673; all predictor variables at visit 2), and 0.673 (95% confidence interval, 0.651-0.694; all predictor variables at visit 3). For all visits, the placental biomarker inhibin A was a valuable predictor, as including inhibin A resulted in better performance in predicting adverse perinatal outcomes (P<.001, all visits). At visit 1, endoglin was also a valuable predictor (P<.001). At visit 2, free beta human chorionic gonadotropin (P=.001) and uterine artery pulsatility index (P=.023) were also valuable predictors. At visit 3, cervical length was also a valuable predictor (P<.001).

CONCLUSION

Despite various advances in predictive modeling in obstetrics, the accurate prediction of adverse perinatal outcomes remains difficult. Interpretable machine learning can help clinicians understand how predictions are made, but barriers exist to the widespread clinical adoption of machine learning models for adverse perinatal outcomes. A better understanding of the evolution of risk factors for adverse perinatal outcomes throughout pregnancy is necessary for the development of effective interventions.

Preterm Birth Among Intrapartum Cesarean Deliveries at Public Hospitals in Southern Ethiopia: A Multicenter Retrospective Analysis of Risk Factors

Purpose

Although the underlying causes for preterm birth are thought to be multifactorial irrespective of delivery mode, no study investigated its risk factors amongst cesarean deliveries (CD). Thus, we aimed to identify potential risk factors for the occurrence of preterm birth (PTB) among intrapartum CD.

Methods

Data from 1659 singleton intrapartum CDs were retrospectively recruited using medical records and an obstetric database. Gestational age was calculated using the last menstrual period (LMP) and ultrasound report of early onset pregnancy. A multivariable logistic regression analysis was performed to identify potential risk factors associated with PTB. Odds ratios (ORs) and 95% confidence intervals (95% CI) were used. Statistical analysis was performed using SPSS version 26.0.

Results

In this study, the prevalence of PTB among intrapartum CD was 6.1% (95% CI: 4.9, 7.2%). In the multivariable logistic regression model; grand parity ≥5 (adjusted odds ratio (AOR) = 2.43, 95% CI: 1.72-4.73), maternal age <20 years (AOR=2.63, 95% CI, 1.03-6.71), maternal age ≥35 years (AOR=3.83, 95% CI, 1.49-5.35), cesarean section scar ≥2 (AOR=4.86, 95% CI: 2.68-8.94), antepartum hemorrhage (AOR=4.37, 95% CI: 2.22-8.63), pregnancy-induced hypertension (AOR=2.92, 95% CI: 1.41-6.04), and premature rupture of membranes (AOR=4.56; 95% CI: 1.95-10.65) were significantly associated with PTB.

Conclusion

The current study showed an association between PTB and a multitude of obstetric variables, including grand parity ≥5, CS scar ≥2, antepartum hemorrhage, pregnancy-induced hypertension, and premature rupture of the membrane. Understanding these factors could help to implement improved quality of obstetric and neonatal care to increase survival and reduce morbidity among preterm birth.

Markers of Cardiovascular Risk Associated with Pregnancy

PURPOSE OF REVIEW

The purpose of the review is to summarize the unique cardiovascular disease (CVD) risk factors encountered during pregnancy and to provide the reader with a framework for acquiring a comprehensive obstetric history during the cardiovascular (CV) assessment of women.

RECENT FINDINGS

Individuals with a history of pregnancies complicated by hypertensive disorders of pregnancy (HDP), gestational diabetes (GDM), preterm delivery, low birth weight, and fetal growth restriction during pregnancy are at a higher risk of developing short- and long-term CV complications compared to those without adverse pregnancy outcomes (APOs). Women with a history of APOs can be at increased risk of CVD even after achieving normoglycemia and normal blood pressure control postpartum. Risk assessment and stratification in women must account for these APOs as recommended by the 2019 American College of Cardiology (ACC)/American Heart Association (AHA) guideline on the primary prevention of CVD. Early recognition, monitoring, and treatment of APOs are key to limiting CVD complications late in maternal life. Recognition of APOs as female-specific cardiovascular risk factors is critical for risk stratification for women and birthing persons. Further research is needed to understand the complex interplay between genetics, environmental, behavioral, and maternal vascular health, and the association between APOs and CVD risk.

Inflammatory Molecules Responsible for Length Shortening and Preterm Birth

It is estimated that inflammation at the placental-maternal interface is directly responsible for or contributes to the development of 50% of all premature deliveries. Chorioamnionitis, also known as the premature rupture of the amniotic membrane in the mother, is the root cause of persistent inflammation that preterm newborns experience. Beyond contributing to the onset of early labor, inflammation is a critical element in advancing several conditions in neonates, including necrotizing enterocolitis, retinopathy of prematurity, bronchopulmonary dysplasia, intraventricular hemorrhage, retinopathy of prematurity and periventricular leukomalacia. Notably, the immune systems of preterm infants are not fully developed; immune defense mechanisms and immunosuppression (tolerance) have a delicate balance that is easily upset in this patient category. As a result, premature infants are exposed to different antigens from elements such as hospital-specific microbes, artificial devices, medications, food antigens and hypoxia/hyperoxia. This has detrimental implications for preterm deliveries of less than 28 weeks because they have not yet evolved the mechanisms to tolerate maternal and self-antigens.

The Predictive Role of Maternal Biological Markers and Inflammatory Scores NLR, PLR, MLR, SII, and SIRI for the Risk of Preterm Delivery

In many countries, preterm birth, defined as birth before 37 completed weeks of gestation, is the primary cause of infant death and morbidity. An increasing body of research suggests that inflammation (both clinical and subclinical) plays a significant role in inducing preterm labor or developing pregnancy problems that lead to premature birth. Consequently, the purpose of this research was to determine the predictive value of the Neutrophil-Lymphocyte Ratio (NLR), derived Neutrophil-Lymphocyte Ratio (dNLR), Monocytes-to-Lymphocyte Ratio (MLR), Platelets-to-Lymphocyte Ratio (PLR), Systemic immune-inflammation index (SII), and systemic inflammatory response index (SIRI), for premature delivery. A retrospective study analyzed a total of 243 eligible pregnancies that resulted in a preterm birth during 2020 and 2021. A control group without a history of preterm birth was matched by age and trimester of laboratory analysis at a 1:1 ratio. Although the number of comorbidities was similar among study groups, the body-mass index estimated for the week of gestation was significantly higher among the patients from the prematurity group, as well as the prevalence of urinary tract infections and smoking. Laboratory data showed that patients with a preterm birth had significantly higher white blood cell count and monocytes, but significantly lower lymphocytes, platelets, and hemoglobin. The NLR, dNLR, PLR, and MLR scores showed to be significantly higher among patients from the prematurity group, but SII and SIRI were not significantly different between the study groups. It was observed that the AUC values of NLR, dNLR, PLR, and MLR were higher than 0.600, respectively NLR had the highest value among the tested scores (AUC = 0.694) and the highest sensitivity in this study (71%). The highest sensibility was achieved by dNLR, with 70%, and an AUC value of 0.655 (p-value = 0.022). PLR had the second-highest AUC value (0.682) and the best score in terms of sensitivity (70%) and sensibility (69%) (p-value = 0.015). Lastly, MLR had the lowest significant AUC score (0.607) and lowest sensitivity/sensibility. The significant cut-off values for the inflammatory scores were 9.0 for NLR, 9.8 for dNLR, 250 for PLR, and 4.07 for MLR. After evaluating the importance of these inflammatory scores, further clinical applications should be conducted to confirm the results and improve therapy and care to reduce the burden of premature deliveries.

Technology-free predictors of preterm birth in singleton women with threatened preterm labor: a prospective cohort study

Background

Prediction of preterm birth is still a challenge due to its multiple etiologies. This prospective cohort study aimed to determine the technology-free predictors of preterm birth in singleton women with threatened preterm labor.

Methods

This prospective cohort study was performed on 371 singleton women with gestational age of 23^+ 6 to 36^+ 4 weeks hospitalized for threatened preterm labor. The data were collected using a questionnaire including demographic characteristics, medical and maternal history, as well as the Perceived Stress Scale (PSS), the Multidimensional Scale of Perceived Social Support (MSPSS), and the WHO’s questionnaire of Violence against Women (VAW). The participants were followed-up until childbirth. The predictors were determined using multivariate logistic regression.

Results

Preterm birth occurred in 51% of women. Seven variables were determined as predictors; rupture of membranes [adjusted odds ratio 11.7, 95% confidence interval 5.4 to 25.6], cervical dilation [AOR 4.1, 95% CI 2.0 to 7.0], gravidity ≥6 [AOR 27.4, 95%CI 2.8 to 264.3], psychological violence during pregnancy [AOR 2.0, 95% CI 1.1 to 3.2], medical problems in pregnancy onset [AOR 1.7, 95% CI 1.1 to 2.8], vaginal bleeding/spotting [AOR 2.1, 95% CI 1.2 to 4.0] and woman age ≤ 19 [AOR 2.2, 95% CI 1.1 to 4.5]. The proportion of variance explained by all these factors was 33.6%.

Conclusions

The technology-free factors seems to have moderate power in preterm birth prediction in singleton pregnant women hospitalized for threatened preterm labor. However, these results are discoveries without verification or validation and need to be confirmed by generalizable studies.

Incidence and Risk Factors for Low Birthweight and Preterm Birth in Post-Conflict Northern Uganda: A Community-Based Cohort Study

BACKGROUND

Annually, an estimated 20 million (13%) low-birthweight (LBW) and 15 million (11.1%) preterm infants are born worldwide. A paucity of data and reliance on hospital-based studies from low-income countries make it difficult to quantify the true burden of LBW and PB, the leading cause of neonatal and under-five mortality. We aimed to determine the incidence and risk factors for LBW and preterm birth in Lira district of Northern Uganda.

METHODS

This was a community-based cohort study, nested within a cluster-randomized trial, designed to study the effect of a combined intervention on facility-based births. In total, 1877 pregnant women were recruited into the trial and followed from 28 weeks of gestation until birth. Infants of 1556 of these women had their birthweight recorded and 1279 infants were assessed for preterm birth using a maturity rating, the New Ballard Scoring system. Low birthweight was defined as birthweight <2.5kg and preterm birth was defined as birth before 37 completed weeks of gestation. The risk factors for low birthweight and preterm birth were analysed using a multivariable generalized estimation equation for the Poisson family.

RESULTS

The incidence of LBW was 121/1556 or 7.3% (95% Confidence interval (CI): 5.4-9.6%). The incidence of preterm births was 53/1279 or 5.0% (95% CI: 3.2-7.7%). Risk factors for LBW were maternal age ≥35 years (adjusted Risk Ratio or aRR: 1.9, 95% CI: 1.1-3.4), history of a small newborn (aRR: 2.1, 95% CI: 1.2-3.7), and maternal malaria in pregnancy (aRR: 1.7, 95% CI: 1.01-2.9). Intermittent preventive treatment (IPT) for malaria, on the other hand, was associated with a reduced risk of LBW (aRR: 0.6, 95% CI: 0.4-0.8). Risk factors for preterm birth were maternal HIV infection (aRR: 2.8, 95% CI: 1.1-7.3), while maternal education for ≥7 years was associated with a reduced risk of preterm birth (aRR: 0.2, 95% CI: 0.1-0.98) in post-conflict northern Uganda.

CONCLUSIONS

About 7.3% LBW and 5.0% PB infants were born in the community of post-conflict northern Uganda. Maternal malaria in pregnancy, history of small newborn and age ≥35 years increased the likelihood of LBW while IPT reduced it. Maternal HIV infection was associated with an increased risk of PB compared to HIV negative status. Maternal formal education of ≥7 years was associated with a reduced risk of PB compared to those with 0-6 years. Interventions to prevent LBW and PBs should include girl child education, and promote antenatal screening, prevention and treatment of malaria and HIV infections.

Metabonomics profile analysis in inflammation-induced preterm birth and the potential role of metabolites in regulating premature cervical ripening

BACKGROUND

Preterm birth (PTB) is the primary cause of infant morbidity and mortality. Moreover, previous studies have established that PTB is related to premature cervical ripening. However, the underlying mechanism remains to be elucidated. This study sought to identify differentially expressed metabolites and investigate their potential biological functions in PTB.

METHODS

Pregnant C57BL/6 J mice were treated with either LPS or normal saline and cervical alterations before labor were detected by staining. Metabolic profiles in the plasma of PTB and control mice were examined through non-targeted metabonomics analyses, quantitative polymerase chain reaction and immunofluorescence staining were performed on human cervical smooth cells.

RESULTS

The study demonstrated that the mRNA and protein levels of α-SMA, SM-22, and calponin in cervical smooth muscle cells of PTB mice were lower while OR was higher at both mRNA and protein levels compared to the CTL group. A total of 181 differentially expressed metabolites were analyzed, among them, 96 were upregulated, while 85 were downregulated in the PTB group. Differentially expressed metabolites may play a role in STAT3, RhoA, mTOR, TGF-β, and NK-κB signaling pathways. Furthermore, when treated with taurine, the levels of α-SMA and SM-22 in human cervical smooth muscle cells were elevated, whereas that of connexin-43 was decreased.

CONCLUSION

Our study highlighted the changes of metabolites in the peripheral blood changed prior to PTB and revealed that these differentially expressed metabolites might participate in the development of premature cervical ripening. Taurine was identified as an important metabolite may modulate human cervical smooth muscle cells. Our study provided new insights into the mechanism underlying premature cervical ripening in PTB.

P2X7 receptor as a potential therapeutic target for perinatal brain injury associated with preterm birth

Inflammation-induced preterm birth is the leading cause of perinatal mortality and long-term sequelae in surviving children. IL-1β is a major contributor to inflammation-induced preterm labor and its sequelae. It has recently been demonstrated that the cytokine storm and its progression depend on IL-1β release into circulation and that the P2X7 receptor (P2X7R) is the key player of the ATP-driven NLRP3/caspase-1 activation, necessary for the cleavage of pro-IL-1β to its mature form as well as its subsequent secretion. Being a key component to the inflammatory cascade, P2X7R illuminates a new therapeutic avenue to halt progression of inflammation prior to perinatal brain injury. In this review, we summarize the basic role of the P2X7 receptor in the inflammatory signaling cascade and the possibility of it being used as a therapeutic target in perinatal brain injury. We discuss the antagonists and agonists of the receptor as well as its role in other inflammatory diseases, showing the importance of discovering the functions of the receptor.

Association between exposures to phthalate metabolites and preterm birth and spontaneous preterm birth: A systematic review and meta-analysis

Emerging evidence from observational studies proves the association between preterm birth (PTB) and phthalate metabolites; however, such findings are inconsistent and inconclusive. This meta-analysis aimed to clarify this association by accessing the connection between 11 phthalate metabolites and PTB, and 6 phthalate metabolites and spontaneous PTB. The PubMed, Embase, and WOS (Web of Science) databases were searched up to July 2020. Seven prospective studies met the inclusion criteria. Pooled odds ratios (OR) with 95% confidence intervals (CIs) were calculated for risk estimation. Our results indicated that mono-n-butyl phthalate (MBP), sum of di-2-ethylhexyl phthalate (ΣDEHP), and mono 3- carboxypropyl phthalate (MCPP) significantly correlated with the risk of PTB (MBP: OR = 1.23, 95% CI = 1.05-1.45; ΣDEHP: OR = 1.21, 95% CI =1.01-1.44; MCPP: OR = 1.09, 95% CI = 1.00-1.19). Pooled results showed that spontaneous PTB was associated with higher urinary levels of mono-ethyl phthalate (MEP), MCPP, mono-isobutyl phthalate (MIBP), and MBP (MBP: OR = 1.27, 95% CI = 1.02-1.58; MEP: OR = 1.19, 95% CI = 1.01-1.40; MCPP: OR = 1.15, 95% CI = 1.02-1.30; MIBP: OR = 1.38, 95% CI = 1.12-1.71). Overall, we conclude that during pregnancy, MBP, ΣDEHP, and MCPP levels are associated positively with PTB. MBP, MEP, MCPP, and MIBP levels had increased odds of spontaneous PTB. No significant associations were observed between other phthalate metabolites and PTB or spontaneous PTB. Further research is needed to verify these findings and elucidate the association of phthalate levels and PTB.

Does Maternal Obesity Affect Preterm Birth? Documentary Cohort Study of Preterm in Firstborns—Silesia (Poland)

In addition to low birth weight and intrauterine growth restriction, prematurity is a major problem in modern neonatology. The etiology of premature delivery is multifactorial, but maternal obesity has been indicated as an important risk factor for preterm birth. This study aimed to assess the relationship between early pregnancy body mass index (BMI) and the risk of preterm delivery according to gestational age. In the cohort of 2794 firstborns, preterm deliveries accounted for 9.1%. Of all deliveries, 16, 48, and 189 were classified as extremely preterm, very preterm, and moderately preterm deliveries, respectively. The risk of extremely, very, and moderately preterm deliveries increased with the increasing BMI, with the highest overweight and obesity-related risk for extremely and very preterm delivery. The rate of extremely and very preterm delivery among normal-weight women (BMI 18.5 ≤ 25) was 1.8%, while that among overweight and obese women (BMI ≥ 25) was 2.36%. The rate of all preterm deliveries (22 ≤ 37 weeks) was 8% for normal-weight women and 10.3% for overweight and obese women. Compared with normal-weight women, the adjusted odds ratio (95% CI) for preterm delivery in overweight and obese women was 1.33 (0.98–1.79). In Poland, being overweight and obese during pregnancy was associated with an increased risk of preterm delivery, especially extremely and very preterm delivery. This relationship should be assessed in other populations.

Validation of a Nomogram for Predicting Preterm Birth in Women With Threatened Preterm Labor: A Prospective Cohort Study in Iranian Tertiary Referral Hospitals

In this prospective cohort study, we aimed to investigate external validity of the Allouche's nomogram to predict preterm birth in symptomatic women in Iran. We employed six variables of cervical length, uterine contractions, rupture of membranes, vaginal bleeding, gestational age, and multiple pregnancy to draw the nomograms. These variables were examined in the first day of women's hospitalization and participants followed up until giving birth. The concordance index of area under the curve (AUC) was used for validation of the nomograms. Of the participants 10% gave birth within 48 hours and 29% before 34 weeks. The nomogram had sufficient accuracy in predicting birth within 48 hours (AUC 0.89 [95% CI 0.82-0.96]) and birth before 34 weeks (AUC 0.89 [95% CI 0.84-0.94]). The optimal risk threshold for nomogram predicting birth within 48 hours was 0.16. Use of these two nomograms, can improve the health of women and their neonates.

Perceived stress and its predictors in women with threatened preterm labour: A cross-sectional study

AIM

To determine prevalence and predictors of perceived stress in women with threatened preterm labour.

DESIGN

Cross-sectional.

METHODS

We recruited 409 women with threatened preterm labour, hospitalized at two tertiary hospitals. We assessed their socio-demographic and obstetrics characteristics, and their perceived stress, perceived social support, experience of violence using validated scales. Multiple linear regression was used to determine the predictors.

RESULTS

Data from all recruited women were analysed. Most of them had borderline (36%) or high (42%) level stress. Overall, 17 predictors were identified explaining 89.5% of variation in the stress score. Predictors of the higher stress score included: urban living, experience of sexual and psychological violence, perceived insufficient social support, experience of vaginal bleeding during current pregnancy, abnormal results in initial pregnancy tests, having multiple roles at home, being less than 28 weeks pregnant, being parous, sleep disorders, history of health problems, insufficient income and unwanted pregnancy.

Labour classified by cervical dilatation & fetal membrane rupture demonstrates differential impact on RNA-seq data for human myometrium tissues

High throughput sequencing has previously identified differentially expressed genes (DEGs) and enriched signalling networks in human myometrium for term (≥37 weeks) gestation labour, when defined as a singular state of activity at comparison to the non-labouring state. However, transcriptome changes that occur during transition from early to established labour (defined as ≤3 and >3 cm cervical dilatation, respectively) and potentially altered by fetal membrane rupture (ROM), when adapting from onset to completion of childbirth, remained to be defined. In the present study, we assessed whether differences for these two clinically observable factors of labour are associated with different myometrial transcriptome profiles. Analysis of our tissue (‘bulk’) RNA-seq data (NCBI Gene Expression Omnibus: GSE80172) with classification of labour into four groups, each compared to the same non-labour group, identified more DEGs for early than established labour; ROM was the strongest up-regulator of DEGs. We propose that lower DEGs frequency for early labour and/or ROM negative myometrium was attributed to bulk RNA-seq limitations associated with tissue heterogeneity, as well as the possibility that processes other than gene transcription are of more importance at labour onset. Integrative analysis with future data from additional samples, which have at least equivalent refined clinical classification for labour status, and alternative omics approaches will help to explain what truly contributes to transcriptomic changes that are critical for labour onset. Lastly, we identified five DEGs common to all labour groupings; two of which (AREG and PER3) were validated by qPCR and not differentially expressed in placenta and choriodecidua.

Effect of Rubus idaeus L. Consumption During Pregnancy on Maternal Mice and Their Offspring

The trigger for human labor is a scientific mystery. This research examined Rubus idaeus (RI), commonly referred to as red raspberry, which is widely purported to be efficacious in promoting parturition processes and favorable birth outcomes. This randomized controlled trial sought to determine the influence of RI consumption during gestation on C57BL/6N Tac mice and their offspring. The aims of this study were to (1) determine differences in the length of gestation, gestational weight gain, and litter size where RI is consumed daily at varied strengths and (2) determine differences in offspring characteristics and behavior where maternal RI consumption occurred. Once paired, mice were randomly assigned to one of three groups: placebo (n = 10) receiving plain water, RI aqueous extract fluid of 1.78 mg/mL (n = 10), or RI aqueous extract fluid of 2.66 mg/mL (n = 10). All received the same standardized diet throughout gestation. Pregnant mice were weighed with chow intake and fluid consumption determined daily. Gestation length and litter size were recorded at the time of birth. Differences in offspring characteristics were also determined and included physical characteristics (weight, physical development) and neuromotor reflexes and behaviors (locomotive abilities, geotaxis reflex, cliff avoidance reflex, and swimming development). When compared with controls, high-dose RI ingestion resulted in shorter length of gestation and smaller litter size (P ≤ .05). There was also an increase in fluid consumption and a decrease in pup weights on postnatal day 4 and 5 with RI treatment (P ≤ .05). Altogether, results suggest that RI influences parturition and fecundity processes with transplacental exposure impacting offspring characteristics.

IL-27 Mediates Pro-Inflammatory Effects via the ERK Signaling Pathway During Preterm Labor

Preterm labor (PTL) is a multifactorial syndrome that results in birth prior to 37 weeks of gestation. However, the specific molecular mechanisms underlying this condition have yet to be elucidated. Previous research demonstrated that the abnormal expression of IL-27, and its receptors, played a role in the pathophysiology of preterm labor. In the present study, we established a Lipopolysaccharide (LPS)-stimulated, infection-induced, preterm mouse model based on wild-type C57BL/6 mice and WSX-1^-/-C57BL/6 mice. WSX-1 knockdown led to a significant delay in birth by 11.32 ± 2.157h. In addition, compared with wild-type C57B/6 mice, the expression levels of IFN-γ, IL-1β, IL-6, TNF-α, and CXCL10, in the fetal membrane and myometrium of WSX-1^-/-mice were significantly lower, particularly in the myometrium. We also confirmed similar pro-inflammatory effects arising from IL-27 in human amniotic cell line (WISH) and human myometrial smooth muscle cell line (HMSMC). Once stimulated by LPS, the pro-inflammatory action exhibited a synergistic effect and appeared to be time-dependent. Finally, we demonstrated that LY3214996, an inhibitor of the ERK pathway, significantly inhibited the pro-inflammatory effect mediated by IL-27. Overall, our data confirmed that the inflammatory effect mediated by the IL-27/IFN-r/ERK axis is involved in preterm labor. Our findings, therefore, provide an enhancement in our etiological understanding of the mechanisms underlying PTL.

17-alpha hydroxyprogesterone caproate for the prevention of recurrent preterm birth among singleton pregnant women with a prior history of preterm birth: a systematic review and meta-analysis of six randomized controlled trials

To perform a systematic review and meta-analysis of all randomized controlled trials (RCTs) that investigated the clinical benefits of 17-alpha hydroxyprogesterone caproate (17OHPC) in the prevention of recurrent preterm birth (PTB) among singleton pregnant women with a previous history of PTB. We searched four major databases up till April 2021 and assessed the risk of bias in the included studies. We meta-analyzed various maternal-neonatal endpoints (n=18) and pooled them as mean difference or risk ratio (RR) with 95% confidence interval (CI) using the random-effects model. Six RCTs met the inclusion criteria, comprising 2,573 patients (17OHPC=1,617, control=956). RCTs revealed an overall low risk of bias. The rates of PTB <35 weeks (n=5 RCTs; RR, 0.77; 95% CI, 0.63–0.93; P=0.008), PTB <32 weeks (n=3 RCTs; RR, 0.68; 95% CI, 0.51–0.91; P=0.009), neonates with low birth weight (<2.5 kg) at delivery (n=3 RCTs; RR, 0.63; 95% CI, 0.5–0.79; P<0.001), and neonatal death (n=4 RCTs; RR, 0.41; 95% CI, 0.20–0.84; P=0.02) were significantly reduced in the 17OHPC group compared with the control group. Moreover, 17OHPC treatment correlated with a significantly decreased rate of retinopathy (n=2 RCTs; RR, 0.42; 95% CI, 0.18–0.97; P=0.004). However, there were no significant differences in the rates of neonatal intensive care unit admission, cesarean delivery, and other preterm-related complications between both the groups. Among singleton pregnant women with a prior history of PTB, 17OHPC may favorably decrease the risks of recurrent PTB and reduce the rate of neonatal death.

Macrophages exert homeostatic actions in pregnancy to protect against preterm birth and fetal inflammatory injury

Macrophages are commonly thought to contribute to the pathophysiology of preterm labor by amplifying inflammation — but a protective role has not previously been considered to our knowledge. We hypothesized that given their antiinflammatory capability in early pregnancy, macrophages exert essential roles in maintenance of late gestation and that insufficient macrophages may predispose individuals to spontaneous preterm labor and adverse neonatal outcomes. Here, we showed that women with spontaneous preterm birth had reduced CD209⁺CD206⁺ expression in alternatively activated CD45⁺CD14⁺ICAM3^– macrophages and increased TNF expression in proinflammatory CD45⁺CD14⁺CD80⁺HLA-DR⁺ macrophages in the uterine decidua at the materno-fetal interface. In Cd11b^DTR/DTR mice, depletion of maternal CD11b⁺ myeloid cells caused preterm birth, neonatal death, and postnatal growth impairment, accompanied by uterine cytokine and leukocyte changes indicative of a proinflammatory response, while adoptive transfer of WT macrophages prevented preterm birth and partially rescued neonatal loss. In a model of intra-amniotic inflammation–induced preterm birth, macrophages polarized in vitro to an M2 phenotype showed superior capacity over nonpolarized macrophages to reduce uterine and fetal inflammation, prevent preterm birth, and improve neonatal survival. We conclude that macrophages exert a critical homeostatic regulatory role in late gestation and are implicated as a determinant of susceptibility to spontaneous preterm birth and fetal inflammatory injury.

Evaluating aminophylline and progesterone combination treatment to modulate contractility and labor-related proteins in pregnant human myometrial tissues

Progesterone (P4) and cyclic adenosine monophosphate (cAMP) are regarded as pro-quiescent factors that suppress uterine contractions during pregnancy. We previously used human primary cells in vitro and mice in vivo to demonstrate that simultaneously enhancing myometrial P4 and cAMP levels may reduce inflammation-associated preterm labor. Here, we assessed whether aminophylline (Ami; phosphodiesterase inhibitor) and P4 can reduce myometrial contractility and contraction-associated proteins (CAPs) better together than individually; both agents are clinically used drugs. Myometrial tissues from pregnant non-laboring women were treated ex vivo with Ami acutely (while spontaneous contracting) or throughout 24-h tissue culture (±P4); isometric tension measurements, PKA assays, and Western blotting were used to assess tissue contractility, cAMP action, and inflammation. Acute (1 h) treatment with 250 and 750 μM Ami reduced contractions by 50% and 84%, respectively, which was not associated with a directly proportional increase in whole tissue PKA activity. Sustained myometrial relaxation was observed during 24-h tissue culture with 750 μM Ami, which did not require P4 nor reduce CAPs. COX-2 protein can be reduced by 300 nM P4 but this did not equate to myometrial relaxation. Ami (250 μM) and P4 (100 and 300 nM) co-treatment did not prevent oxytocin-augmented contractions nor reduce CAPs during interleukin-1β stimulation. Overall, Ami and P4 co-treatment did not suppress myometrial contractions more than either agent alone, which may be attributed to low specificity and efficacy of Ami; cAMP and P4 action at in utero neighboring reproductive tissues during pregnancy should also be considered.

Cervical length distribution and other sonographic ancillary findings of singleton nulliparous patients at midgestation

BACKGROUND

Short cervix at midgestation, the presence of intraamniotic debris, and cervical funneling are risk factors for preterm birth; however, cervical length measurements and cutoffs are not well documented among pregnant patients of different gestational ages and self-reported races and ethnicities.

OBJECTIVE

This study aimed to describe the distribution of cervical length and frequency of funneling and debris at midgestation in nulliparous women by gestational age and race/ethnicity.

STUDY DESIGN

This secondary analysis of screening data from a multicenter treatment trial of singleton nulliparous patients with short cervix was conducted at 14 geographically distributed, university-affiliated medical centers in the United States. Singleton nulliparous patients with no known risk factors for preterm birth were screened for trial participation and asked to undergo a transvaginal ultrasound to measure cervical length by a certified sonographer. The distribution of cervical length and the frequency of funneling and debris were assessed for each gestational age week (16-22 weeks) and stratified by self-reported race and ethnicity, which for this study were categorized as White, Black, Hispanic, and other. Patients enrolled in the randomized trial were excluded from this analysis.

RESULTS

A total of 12,407 nulliparous patients were included in this analysis. The racial or ethnic distribution of the study participants was as follows: White, 41.6%; Black, 29.6%; Hispanic, 24.2%; and others, 4.6%. The 10th percentile cervical length for the entire cohort was 31.1 mm and, when stratified by race and ethnicity, 31.9 mm for White, 30.2 mm for Black, 31.4 mm for Hispanic, and 31.2 mm for patients of other race and ethnicity (P<.001). At each gestational age, the cervical length corresponding to the tenth percentile was shorter in Black patients. The 25 mm value commonly used to define a short cervix and thought to represent the 10th percentile ranged from 1.3% to 5.4% across gestational age weeks and 1.0% to 3.8% across race and ethnicity groups. Black patients had the highest rate of funneling (2.6%), whereas Hispanic and Black patients had higher rates of intraamniotic debris than White and other patients (P<.001).

CONCLUSION

Black patients had shorter cervical length and higher rates of debris and funneling than White patients. The racial and ethnic disparities in sonographic midtrimester cervical findings may provide insight into the racial disparity in preterm birth rates in the United States.

Comparison of Genome-Wide DNA Methylation Profiles of Human Fetal Tissues Conceived by in vitro Fertilization and Natural Conception

Background

Assisted reproductive technology (ART) might induce adverse pregnancy outcomes and increase the risk of metabolic diseases in offspring' later life with unknown reasons. Here we evaluated the global methylation level and methylation profile of fetal tissue from elective terminations of pregnancy (ETP) after natural conception and multifetal pregnancy reduction (MFPR) after in vitro fertilization and embryo transfer (IVF-ET).

Results

Global methylation levels were comparable between the fetal tissue of ETP after natural conception group and MFPR after IVF-ET group. The methylation levels were lower in the hypermethylated regions of the MFPR group than in the ETP group, while the methylation levels were higher in the hypomethylated regions of the MFPR group. Heatmap visualization and hierarchical clustering of the candidate differentially methylated regions (DMRs) showed differences between the DMRs in the ETP and MFPR samples. We identified 196 differentially methylated regions that matched 164 genes between the ETP and MFPR groups. In the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, skeletal system morphogenesis and diabetes mellitus ranked first. Ingenuity Pathway Analysis (IPA) revealed 8 diseases and functional annotations associated with IVT-ET. In the MFPR group, the final validation showed lower methylation levels in gene bodies of bone morphogenetic protein 4 (BMP4), higher methylation levels in the 1st exon and 5'UTR of thyroid peroxidase (TPO), and higher methylation levels in TSS1500 and TSS200 of interleukin 1 beta (IL1B).

Conclusions

ART does not alter global DNA methylation level, but influences DNA methylation variation in specific regions of human fetus in the early stage of life. Further studies are warranted to clarify the potential role of DNA methylation alterations in the gene expression profile.

Elevated methylation of the vault RNA2-1 promoter in maternal blood is associated with preterm birth

Background

Preterm birth, defined as parturition before 37 completed weeks of gestation, is associated with an increased risk of neonatal complications and death, as well as poor health and disease later in life. Epigenetics could contribute to the mechanism underlying preterm birth.

Results

Genome-wide DNA methylation analysis of whole blood cells from 10 women (5 term and 5 preterm deliveries) was performed using an Illumina Infinium HumanMethylation450 BeadChips array. We identified 1,581 differentially methylated CpG sites in promoter regions between term and preterm birth. Although the differences were not significant after correcting for multiple tests, seven CpGs on the genomically imprinted vault RNA2-1 (VTRNA2-1; also known as non-coding RNA, nc886 or miR-886) showed the largest differences (range: 26–39 %). Pyrosequencing verification was performed with blood samples from pregnant women recruited additionally (39 term and 43 preterm deliveries). In total, 28 (34.1 %) samples showed hypomethylation of the VTRNA2-1 promoter (< 13 % methylation), while 54 (65.9 %) samples showed elevated methylation levels between 30 and 60 %. Elevated methylation of VTRNA2-1 promoter was associated with an increased risk of preterm birth after adjusting for maternal age, season of delivery, parity and white blood cell count. The mRNA expression of VTRNA2-1 was 0.51-fold lower in women with preterm deliveries (n = 20) compared with women with term deliveries (n = 20).

Conclusions

VTRNA2-1 is a noncoding transcript to environmentally responsive epialleles. Our results suggest that elevated methylation of the VTRNA2-1 promoter may result in increased risk of PTB caused by the pro-inflammatory cytokines. Further studies are needed to confirm the association of VTRNA2-1 methylation with preterm birth in a large population, and to elucidate the underlying mechanism.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07865-y.

Identification of Indicators for Preterm Birth Using Retinoid Metabolites

Metabolites reflect the biochemical dynamics for the maintenance of pregnancy and parturition. UPLC-Q/TOF-MS and LC-MS/MS metabolomics were performed to identify and validate the plasma metabolomic signatures of preterm birth (PTB). We recruited pregnant women between 16 and 40 weeks 5 days gestational age at Ewha Womans Mokdong Hospital for a nested case-control study. In untargeted UPLC-Q/TOF-MS, score plots of partial least-squares discriminant analysis clearly separated the PTB group from the term birth (TB, n = 10; PTB, n = 11). Fifteen metabolites were significantly different between the two groups, as indicated by a variable importance in projection >1 and p < 0.05. Metabolic pathways involving retinol, linoleic acid, d-arginine, and d-ornithine were associated with PTB. Verification by LC-MS/MS focused on retinol metabolism (TB, n = 39; PTB, n = 20). Retinol levels were significantly reduced in PTB compared to TB, while retinal palmitate, all-trans-retinal, and 13-cis-retinoic acid (¹³cis-RA) significantly increased (p < 0.05). Retinol-binding protein levels were also elevated in PTB. Additionally, all-trans-retinal (AUC 0.808, 95% CI: 0.683–0.933) and ¹³cis-RA (AUC 0.826, 95% CI: 0.723–0.930) showed improved predictions for PTB-related retinol metabolites. This study suggests that retinoid metabolism improves the accuracy of PTB predictions and plays an important role in maintaining pregnancy and inducing early parturition.

Inflammatory factors, genetic variants, and predisposition for preterm birth

Preterm birth is a major clinical and public health challenge, with a prevalence of 11% worldwide. It is the leading cause of death in children younger than 5 years old and represents 70% of neonatal deaths and 75% of neonatal morbidity. Despite the clinical and public health significance, this condition's etiology is still unclear, and most of the cases are spontaneous. There are several known preterm birth risk factors, including inflammatory diseases and the genetic background, although the underlying molecular mechanisms are far from understood. The present review highlights the research advances on the association between inflammatory-related genes and the increased risk for preterm delivery. The most associated genetic variants are the TNFα rs1800629, the IL1α rs17561, and the IL1RN rs2234663. Moreover, many of the genes discussed in this review are also implicated in pathologies involving inflammatory or autoimmune systems, such as periodontal disease, bowel inflammatory disease, and autoimmune rheumatic diseases. This review presents evidence suggesting a common genetic background to preterm birth, autoimmune and inflammatory diseases susceptibility.

S100B protein, cerebral ultrasound and magnetic resonance imaging patterns in brain injured preterm infants

OBJECTIVES

The early detection of preterm infants (PI) at risk for intraventricular hemorrhage (IVH) and neurological sequelae still constitutes an unsolved issue. We aimed at validating the role of S100B protein in the early diagnosis and prognosis of IVH in PI by means of cerebral ultrasound (CUS) and magnetic resonance imaging (MRI) today considered standard of care procedures.

METHODS

We conducted an observational case-control study in 216 PI of whom 36 with IVH and 180 controls. Standard clinical, laboratory, radiological monitoring procedures and S100B urine measurement were performed at four time-points (first void, 24, 48, 96 h) after birth. Cerebral MRI was performed at 40-42 weeks of corrected gestational age.

RESULTS

Elevated (p<0.001, for all) S100B levels were observed in the IVH group at all monitoring time-point particularly at first void when standard monitoring procedures were still silent or unavailable. S100B measured at first void correlated (p<0.001) with the grade of hemorrhage by means of CUS and with the site and extension of neurological lesion (p<0.001, for all) as assessed by MRI.

CONCLUSIONS

The present results showing a correlation among S100B and CUS and MRI offer additional support to the inclusion of the protein in clinical daily management of cases at risk for IVH and adverse neurological outcome. The findings open the way to further investigations in PI aimed at validating new neurobiomarkers by means of S100B.

Transcription factors regulated by cAMP in smooth muscle of the myometrium at human parturition

Cyclic adenosine monophosphate (cAMP) contributes to maintenance of a quiescent (relaxed) state in the myometrium (i.e. uterine smooth muscle) during pregnancy, which most commonly has been attributed to activation of protein kinase A (PKA). PKA-mediated phosphorylation of cytosolic contractile apparatus components in myometrial smooth muscle cells (mSMCs) are known to promote relaxation. Additionally, PKA also regulates nuclear transcription factor (TF) activity to control expression of genes important to the labour process; these are mostly involved in actin-myosin interactions, cell-to-cell connectivity and inflammation, all of which influence mSMC transition from a quiescent to a contractile (pro-labour) phenotype. This review focuses on the evidence that cAMP modulates the activity of TFs linked to pro-labour gene expression, predominantly cAMP response element (CRE) binding TFs, nuclear factor κB (NF-κB), activator protein 1 (AP-1) family and progesterone receptors (PRs). This review also considers the more recently described exchange protein directly activated by cAMP (EPAC) that may oppose the pro-quiescent effects of PKA, as well as explores findings from other cell types that have the potential to be of novel relevance to cAMP action on TF function in the myometrium.

Influence of Placental Abnormalities and Pregnancy-Induced Hypertension in Prematurity Associated with Various Assisted Reproductive Technology Techniques

OBJECTIVE

Assisted reproductive technology (ART)-treated women exhibit increased risk of premature delivery compared to fertile women. We evaluated whether ART treatment modalities increase prematurity and whether placental abnormalities and pregnancy-induced hypertensive (PIH) disorders mediate these risks.

METHOD(S)

This retrospective study of ART-treated and fertile deliveries (2004-2017) used an ART-cycle database linked to Massachusetts birth certificates and hospital discharges. Outcomes of late preterm birth (LPTB: 34-36 weeks gestation) and early preterm birth (EPTB: <34 weeks gestation) were compared with term deliveries (≥37 weeks gestation) in ART-treated (linked to the ART database) and fertile (no indicators of infertility or ART) deliveries. ART treatments with autologous oocyte, donor oocyte, fresh or frozen embryo transfer (FET), intracytoplasmic sperm injection (ICSI) and no-ICSI were separately compared to the fertile group. Adjusted odds ratios (AOR) were calculated with multivariable logistic regression: placental abnormalities or PIH were quantified in the pathway as mediators.

RESULTS

There were 218,320 deliveries: 204,438 fertile and 13,882 ART-treated. All treatment types increased prematurity (AOR 1.31-1.58, LPTB; AOR 1.34-1.48, EPTB). Placental abnormalities mediated in approximately 22% and 38% of the association with LPTB and EPTB, respectively. PIH mediated 25% and 33% of the association with LPTB and EPTB in FET and donor oocyte cycles, more than other treatments (<10% LPTB and <13% EPTB).

CONCLUSIONS

ART-treatment and all ART modalities increased LPTB and EPTB when compared with fertile deliveries. Placental abnormalities modestly mediated associations approximately equally, while PIH was a stronger mediator in FET and donor oocyte cycles. Reasons for differences require exploration.

The influence of race on cervical length in pregnant women in Brazil

OBJECTIVES

Short cervical length is a predictor of preterm birth. We evaluated if there were racial differences in variables associated with cervical length in pregnant Brazilian women.

METHODS

Cervical length was determined by vaginal ultrasound in 414 women at 21 weeks gestation. All women were seen at the same clinic and analyzed by the same investigators. Women found to have a short cervix (≤25 mm) received vaginal progesterone throughout gestation. Composition of the vaginal microbiome was determined by analysis of the V1-V3 region of the gene coding for bacterial 16S ribosomal RNA. Demographic, clinical and outcome variables were determined by chart review. Subjects were 53.4% White, 37.2% mixed race and 9.4% Black.

RESULTS

Pregnancy, medical history and education level were similar in all groups. Mean cervical length was shorter in Black women (28.4 mm) than in White (32.4 mm) or mixed race (32.8 mm) women (p≤0.016) as was the percentage of women with a short cervix (23.1, 12.2, 7.8% in Black, White, mixed race respectively) (p≤0.026). Mean cervical length increased with maternal age in White (p=0.001) and mixed race (p=0.045) women but not Black women. There were no differences in bacterial dominance in the vaginal microbiota between groups. Most women with a short cervix delivered at term.

CONCLUSIONS

We conclude that Black women in Brazil have a shorter cervical length than White or mixed race women independent of maternal age, pregnancy and demographic history or composition of the vaginal microbiome.

Long-Term IoT-Based Maternal Monitoring: System Design and Evaluation

Pregnancy is a unique time when many mothers gain awareness of their lifestyle and its impacts on the fetus. High-quality care during pregnancy is needed to identify possible complications early and ensure the mother’s and her unborn baby’s health and well-being. Different studies have thus far proposed maternal health monitoring systems. However, they are designed for a specific health problem or are limited to questionnaires and short-term data collection methods. Moreover, the requirements and challenges have not been evaluated in long-term studies. Maternal health necessitates a comprehensive framework enabling continuous monitoring of pregnant women. In this paper, we present an Internet-of-Things (IoT)-based system to provide ubiquitous maternal health monitoring during pregnancy and postpartum. The system consists of various data collectors to track the mother’s condition, including stress, sleep, and physical activity. We carried out the full system implementation and conducted a real human subject study on pregnant women in Southwestern Finland. We then evaluated the system’s feasibility, energy efficiency, and data reliability. Our results show that the implemented system is feasible in terms of system usage during nine months. We also indicate the smartwatch, used in our study, has acceptable energy efficiency in long-term monitoring and is able to collect reliable photoplethysmography data. Finally, we discuss the integration of the presented system with the current healthcare system.

Progesterone receptor isoform B regulates the Oxtr-Plcl2-Trpc3 pathway to suppress uterine contractility

Uterine contractile dysfunction leads to pregnancy complications such as preterm birth and labor dystocia. In humans, it is hypothesized that progesterone receptor isoform PGR-B promotes a relaxed state of the myometrium, and PGR-A facilitates uterine contraction. This hypothesis was tested in vivo using transgenic mouse models that overexpress PGR-A or PGR-B in smooth muscle cells. Elevated PGR-B abundance results in a marked increase in gestational length compared to control mice (21.1 versus 19.1 d respectively, P < 0.05). In both ex vivo and in vivo experiments, PGR-B overexpression leads to prolonged labor, a significant decrease in uterine contractility, and a high incidence of labor dystocia. Conversely, PGR-A overexpression leads to an increase in uterine contractility without a change in gestational length. Uterine RNA sequencing at midpregnancy identified 1,174 isoform-specific downstream targets and 424 genes that are commonly regulated by both PGR isoforms. Gene signature analyses further reveal PGR-B for muscle relaxation and PGR-A being proinflammatory. Elevated PGR-B abundance reduces Oxtr and Trpc3 and increases Plcl2 expression, which manifests a genetic profile of compromised oxytocin signaling. Functionally, both endogenous PLCL2 and its paralog PLCL1 can attenuate uterine muscle cell contraction in a CRISPRa-based assay system. These findings provide in vivo support that PGR isoform levels determine distinct transcriptomic landscapes and pathways in myometrial function and labor, which may help further the understanding of abnormal uterine function in the clinical setting.

Decidual cell FKBP51-progesterone receptor binding mediates maternal stress-induced preterm birth

Depression and posttraumatic stress disorder increase the risk of idiopathic preterm birth (iPTB); however, the exact molecular mechanism is unknown. Depression and stress-related disorders are linked to increased FK506-binding protein 51 (FKBP51) expression levels in the brain and/or FKBP5 gene polymorphisms. Fkbp5-deficient (Fkbp5 ^-/-) mice resist stress-induced depressive and anxiety-like behaviors. FKBP51 binding to progesterone (P4) receptors (PRs) inhibits PR function. Moreover, reduced PR activity and/or expression stimulates human labor. We report enhanced in situ FKBP51 expression and increased nuclear FKBP51-PR binding in decidual cells of women with iPTB versus gestational age-matched controls. In Fkbp5 ^+/+ mice, maternal restraint stress did not accelerate systemic P4 withdrawal but increased Fkbp5, decreased PR, and elevated AKR1C18 expression in uteri at E17.25 followed by reduced P4 levels and increased oxytocin receptor (Oxtr) expression at 18.25 in uteri resulting in PTB. These changes correlate with inhibition of uterine PR function by maternal stress-induced FKBP51. In contrast, Fkbp5 ^-/- mice exhibit prolonged gestation and are completely resistant to maternal stress-induced PTB and labor-inducing uterine changes detected in stressed Fkbp5 ^+/+ mice. Collectively, these results uncover a functional P4 withdrawal mechanism mediated by maternal stress-induced enhanced uterine FKBP51 expression and FKPB51-PR binding, resulting in iPTB.

Trophoblastic extracellular vesicles and viruses: Friends or foes?

Cells produce cytoplasmic vesicles to facilitate the processing and transport of RNAs, proteins, and other signaling molecules among intracellular organelles. Moreover, most cells release a range of extracellular vesicles (EVs) that mediate intercellular communication in both physiological and pathological settings. In addition to a better understanding of their biological functions, the diagnostic and therapeutic prospects of EVs, particularly the nano-sized small EVs (sEVs, exosomes), are currently being rigorously pursued. While EVs and viruses such as retroviruses might have evolved independently, they share a number of similar characteristics, including biogenesis pathways, size distribution, cargo, and cell-targeting mechanisms. The interplay of EVs with viruses has profound effects on viral replication and infectivity. Our research indicates that sEVs, produced by primary human trophoblasts, can endow other non-placental cell types with antiviral response. Better insights into the interaction of EVs with viruses may illuminate new ways to attenuate viral infections during pregnancy, and perhaps develop new antiviral therapeutics to protect the feto-placental unit during critical times of human development.

The Association of Inflammatory Biomarker of Neutrophil-to-Lymphocyte Ratio with Spontaneous Preterm Delivery: A Systematic Review and Meta-analysis

BACKGROUND

Neutrophil-to-lymphocyte ratio (NLR), as an inflammatory biomarker, has been investigated in several studies for early prediction of preterm delivery. However, their findings seem to be controversial. Thus, this systematic review and meta-analysis was conducted to evaluate the role of NLR in predicting preterm delivery as compared to term controls.

METHODS

PubMed, Web of Science, Embase, Scopus, and Google Scholar were systematically searched from inception up to December 2020. Interstudy heterogeneity was assessed using Cochrane's Q test and the I 2 statistic. The random-effects model was employed to pool the weighted mean differences (WMDs) and the corresponding 95% confidence intervals (CIs).

RESULTS

Out of a total of 4369 recodes, fifteen articles including 3327 participants were enrolled. The meta-analysis finding using the random-effects model produced a pooled estimate suggesting a significantly higher NLR (WMD = 1.23, 95% CI: 0.40-2.07) in women with preterm delivery (P = 0.01). We found significant heterogeneity across the included studies (P < 0.001, I 2 = 92.33%). However, interstudy heterogeneity exists mainly due to differences in the definition of preterm delivery (I 2 = 0.0%). In the metaregression analysis, there was no significant effect of publication year (B = -0.288, P = 0.088), total sample size (B = -0.002, P = 0.276), and the mean age of cases (B = -0.06, P = 0.692) on the association between NLR and preterm delivery.

CONCLUSION

The results of this meta-analysis revealed that the NLR value is higher in patients with preterm delivery. The NLR could be a useful biomarker for predicting preterm delivery; however, further prospective case-control studies are required to produce stronger evidence.

Determinants of preterm birth among women delivered in public hospitals of Western Ethiopia, 2020: Unmatched case-control study

BACKGROUND

Worldwide, preterm birth accounts for 1 million deaths of infants each year and 60% of these deaths occur in developing countries. In addition to the significant health consequences on the infant, preterm birth can lead to economic costs. There was a lack of study in western Ethiopia, and most of those studies conducted in other parts of a country were based on card review with a cross-sectional study design. The risk factors of preterm birth may vary from region to region within the same country due to variation in socioeconomic status and health care service coverage. Therefore, this study aimed to identify determinants of preterm birth in western Ethiopia.

METHODS

An institutional-based case-control study was conducted from February 15 to April 15, 2020, in western Ethiopia. The eligible 188 cases and 377 controls were randomly selected for this study. Cases were women who gave birth after 28 weeks and before 37 completed weeks of gestation, and controls were women who gave birth at and after 37 weeks of gestation from the first day of the last normal menstrual period. Data were collected by a structured interviewer-administered questionnaire. The collected data were entered into Epi info version 7 and exported to SPSS version 21 for analysis. Multivariable logistic regression was used to identify determinants of preterm birth at P-value <0.05.

RESULTS

From a total of 565 eligible participants, 516 (172 cases and 344 controls) participated in this study with a response rate of 91.3%. The result of the multivariable analysis shows that mothers who developed pregnancy-induced hypertension (AOR = 3.13, 95% CI; 1.78, 5.50), only one time ANC visits (AOR = 5.99, 95% CI; 2.65, 13.53), experienced premature rupture of membrane (AOR = 3.57, 95% CI; 1.79, 7.13), birth interval less than two years (AOR = 2.96, 95% CI; 1.76, 4.98), developed anemia during the current pregnancy (AOR = 4.20, 95% CI; 2.13, 8.28) and didn't get dietary supplementation during the current pregnancy (AOR = 2.43, 95% CI; 1.51, 3.91) had statistically significant association with experiencing preterm birth.

CONCLUSION

Antenatal care service providers should focus on mothers with pregnancy-induced hypertension, premature rupture of membrane, and anemia during pregnancy, and refer to the senior experts for early management to reduce the risk of preterm delivery. Antenatal care services such as counseling the mother on the benefit of dietary supplementation during pregnancy, antenatal care follow up, and lengthening birth interval should be integrated into the existing health extension packages. New and inclusive strategies such as the establishment of comprehensive mobile clinic services should also be designed to reduce the burden of preterm birth among women living in the rural community. Lastly, we recommend future researchers to conduct longitudinal and community-based studies supplemented with qualitative methods.

Incidence of influenza during pregnancy and association with pregnancy and perinatal outcomes in three middle-income countries: a multisite prospective longitudinal cohort study

BACKGROUND

Influenza vaccination during pregnancy prevents influenza among women and their infants but remains underused among pregnant women. We aimed to quantify the risk of antenatal influenza and examine its association with perinatal outcomes.

METHODS

We did a prospective cohort study in pregnant women in India, Peru, and Thailand. Before the 2017 and 2018 influenza seasons, we enrolled pregnant women aged 18 years or older with expected delivery dates 8 weeks or more after the season started. We contacted women twice weekly until the end of pregnancy to identify illnesses with symptoms of myalgia, cough, runny nose or nasal congestion, sore throat, or difficulty breathing and collected mid-turbinate nasal swabs from symptomatic women for influenza real-time RT-PCR testing. We assessed the association of antenatal influenza with preterm birth, late pregnancy loss (≥13 weeks gestation), small for gestational age (SGA), and birthweight of term singleton infants using Cox proportional hazards models or generalised linear models to adjust for potential confounders.

FINDINGS

Between March 13, 2017, and Aug 3, 2018, we enrolled 11 277 women with a median age of 26 years (IQR 23-31) and gestational age of 19 weeks (14-24). 1474 (13%) received influenza vaccines. 310 participants (3%) had influenza (270 [87%] influenza A and 40 [13%] influenza B). Influenza incidences weighted by the population of women of childbearing age in each study country were 88·7 per 10 000 pregnant woman-months (95% CI 68·6 to 114·8) during the 2017 season and 69·6 per 10 000 pregnant woman-months (53·8 to 90·2) during the 2018 season. Antenatal influenza was not associated with preterm birth (adjusted hazard ratio [aHR] 1·4, 95% CI 0·9 to 2·0; p=0·096) or having an SGA infant (adjusted relative risk 1·0, 95% CI 0·8 to 1·3, p=0·97), but was associated with late pregnancy loss (aHR 10·7, 95% CI 4·3 to 27·0; p<0·0001) and reduction in mean birthweight of term, singleton infants (-55·3 g, 95% CI -109·3 to -1·4; p=0·0445).

INTERPRETATION

Women had a 0·7-0·9% risk of influenza per month of pregnancy during the influenza season, and antenatal influenza was associated with increased risk for some adverse pregnancy outcomes. These findings support the added value of antenatal influenza vaccination to improve perinatal outcomes.

FUNDING

US Centers for Disease Control and Prevention.

TRANSLATIONS

For the Thai, Hindi, Marathi and Spanish translations of the abstract see Supplementary Materials section.

Assessing the quality of antenatal corticosteroids in low- and middle-income countries: A systematic review

Background

The World Health Organization (WHO) recommends the administration of intramuscular antenatal corticosteroids to women at risk of preterm birth to prevent preterm-associated neonatal mortality and morbidity. Poor quality medicines are a major problem for health services in low- and middle-income countries (LMICs), however the quality of antenatal corticosteroids is not well understood. We aimed to conduct a systematic review of available studies describing the quality of recommended injectable antenatal corticosteroids (dexamethasone or betamethasone) in LMICs.

Methods

Structured search strategy was applied to six databases (MEDLINE, EMBASE, CINAHL, International Pharmaceutical Abstracts, Global Index Medicus, WHO Medicines Quality Database), without year or language restrictions. Any primary study reporting any medicine quality parameter (Active Pharmacological Ingredient, pH and sterility) for injectable dexamethasone or betamethasone was eligible. Two authors independently screened studies for eligibility, extracted data on included studies and applied Medicine Quality Assessment Reporting Guidelines tool to assess study quality. Results were reported narratively, stratified by country of manufacture, organisation type and level of care.

Results

In total, 15,547 citations were screened with two eligible studies identified that focussed on dexamethasone quality (no studies of betamethasone were identified). One study included 19 samples from 9 LMICs, and the other included “less than 100 samples” from India. The prevalence of failed dexamethasone samples ranged from 3.14% to 32.2% due to inadequate Active Pharmacological Ingredient. A higher prevalence of failed dexamethasone samples were seen at the point of care and the public sector.

Conclusions

Poor quality maternal and newborn health medicines can endanger women and newborns. Though available evidence on antenatal corticosteroids quality in LMICs is limited, results suggested poor quality dexamethasone may be prevalent in some countries. More primary studies are required to confirm these findings and guide policymakers on procurement of good-quality maternal and newborn health medicines.

Risk factors for spontaneous preterm delivery

BACKGROUND

There is a substantial variation in rates of preterm delivery between different parts of the world. The understanding of these variations, as well as the biological mechanisms behind spontaneous preterm delivery, is limited. Although the benefit of antenatal interventions has been shown to be limited, using well-known risk factors for spontaneous preterm delivery to select the correct pregnant women for targeted interventions is important from both a medical and caregiving perspective.

OBJECTIVE

To provide an introduction to a substantial research area dealing with risk factors of spontaneous preterm delivery.

METHODS

Risk factors in this review were classified as demographical, obstetrical, and gynecological and those related to the current pregnancy according to high-quality evidence of recent literature.

RESULTS AND CONCLUSION

An introduction to a substantial research area in maternal and fetal medicine was provided that might help clinicians to better understand the risk factors related to preterm delivery and select the correct pregnant women for targeted interventions.

Microbiota-Dependent Effects of IL-22

Cytokines are important contributors to immune responses against microbial and environmental threats and are of particular importance at epithelial barriers. These interfaces are continuously exposed to external factors and thus require immune components to both protect the host from pathogen invasion and to regulate overt inflammation. Recently, substantial efforts have been devoted to understanding how cytokines act on certain cells at barrier sites, and why the dysregulation of immune responses may lead to pathogenesis. In particular, the cytokine IL-22 is involved in preserving an intact epithelium, maintaining a balanced microbiota and a functioning defense system against external threats. However, a tight regulation of IL-22 is generally needed, since uncontrolled IL-22 production can lead to the progression of autoimmunity and cancer. Our aim in this review is to summarize novel findings on IL-22 and its interactions with specific microbial stimuli, and subsequently, to understand their contributions to the function of IL-22 and the clinical outcome. We particularly focus on understanding the detrimental effects of dysregulated control of IL-22 in certain disease contexts.

Intraventricular Hemorrhage and White Matter Injury in Preclinical and Clinical Studies

Germinal matrix-intraventricular hemorrhage (IVH) occurs in nearly half of infants born at less than 26 weeks' gestation. Up to 50% of survivors with IVH develop cerebral palsy, cognitive deficits, behavioral disorders, posthemorrhagic ventricular dilatation, or a combination of these sequelae. After the initial bleeding and the primary brain injury, inflammation and secondary brain injury might lead to periventricular leukomalacia or diffuse white matter injury. Potential factors that are involved include microglia and astrocyte activation, degradation of blood components with release of "toxic" products, infiltration of the brain by systemic immune cells, death of neuronal and glial cells, and arrest of preoligodendrocyte maturation. In addition, impairment of the blood-brain barrier may play a major role in the pathophysiology. A wide range of animal models has been used to explore causes and mechanisms leading to IVH-induced brain injury. Preclinical studies have identified potential targets for enhancing brain repair. However, little has been elucidated about the effectiveness of potential interventions in clinical studies. A systematic review of available preclinical and clinical studies might help identify research gaps and which types of interventions may be prioritized. Future trials should report clinically robust and long-term outcomes after IVH.

Novel pathways of inflammation in human fetal membranes associated with preterm birth and preterm pre-labor rupture of the membranes

Spontaneous preterm birth (PTB) and preterm pre-labor rupture of the membranes (pPROM) are major pregnancy complications. Although PTB and pPROM have common etiologies, they arise from distinct pathophysiologic pathways. Inflammation is a common underlying mechanism in both conditions. Balanced inflammation is required for fetoplacental growth; however, overwhelming inflammation (physiologic at term and pathologic at preterm) can lead to term and preterm parturition. A lack of effective strategies to control inflammation and reduce the risk of PTB and pPROM suggests that there are several modes of the generation of inflammation which may be dependent on the type of uterine tissue. The avascular fetal membrane (amniochorion), which provides structure, support, and protection to the intrauterine cavity, is one of the key contributors of inflammation. Localized membrane inflammation helps tissue remodeling during pregnancy. Two unique mechanisms that generate balanced inflammation are the progressive development of senescence (aging) and cyclic cellular transitions: epithelial to mesenchymal (EMT) and mesenchymal to epithelial (MET). The intrauterine build-up of oxidative stress at term or in response to risk factors (preterm) can accelerate senescence and promote a terminal state of EMT, resulting in the accumulation of inflammation. Inflammation degrades the matrix and destabilizes membrane function. Inflammatory mediators from damaged membranes are propagated via extracellular vesicles (EV) to maternal uterine tissues and transition quiescent maternal uterine tissues into an active state of labor. Membrane inflammation and its propagation are fetal signals that may promote parturition. This review summarizes the mechanisms of fetal membrane cellular senescence, transitions, and the generation of inflammation that contributes to term and preterm parturitions.