Risk Factors For Spontaneous Preterm Birth Research Articles

Prenatal exposure to fine particulate matter and the risk of spontaneous preterm birth: A population-based cohort study of twins.

Studies in singletons have suggested that prenatal exposure to fine particulate matter (PM2.5) and some of its chemical components is associated with an increased risk of preterm birth (PTB). However, no study has been conducted in twins. To examine the associations of maternal exposure to total PM2.5 mass and its carbonaceous components with PTB in twin pregnancies. A total of 1,515 pairs of twins and their mothers were enrolled from a previous twin birth cohort that had been conducted at the Shanghai First Maternity and Infant Hospital School of Medicine of Tongji University in China. Participants who had iatrogenic PTBs were excluded. Maternal exposure to total PM2.5 mass and two carbonaceous components, namely, organic carbon (OC) and black carbon (BC), was estimated by a satellite-based model. The associations between PM2.5 exposure and the risk of spontaneous PTB were evaluated by logistic regression analysis. This study found that exposure to total PM2.5 mass and OC during the second trimester of pregnancy was significantly associated with an increased risk of spontaneous PTB. An interquartile range (IQR) increase in total PM2.5 mass and OC exposure during the second trimester was associated with 48% (OR = 1.48, 95% CI, 1.06, 2.05) and 50% (OR = 1.50, 95% CI, 1.00, 2.25) increases in the odds of PTB, respectively. However, no significant association was found between BC exposure during any exposure window and the risk of PTB. The findings suggest that exposure to ambient air pollution with fine particles may be a risk factor for spontaneous PTB in twin pregnancies. The middle stage of pregnancy seems to be a critical window for the impacts of PM2.5 exposure on PTB in twin pregnancies.

Population attributable fractions for risk factors for spontaneous preterm births in 81 low- and middle-income countries: A systematic analysis.

BackgroundComplications associated with preterm birth (PTB) are the largest contributor to under-five mortality globally. Success in reaching the Sustainable Development Goal target requires identifying potentially modifiable risk factors for PTB, estimating the relative importance of these risk factors, and identifying/implementing effective prevention strategies to address them.MethodsWe conducted a literature review to define risk relationships and estimate prevalence for established risk factors for spontaneous PTB (sPTB). We then estimated population attributable fractions (PAF) for the sPTB risk factors identified in the review as statistically significant for the 81 low- and middle-income (LMIC) countries included in the Countdown 2030 initiative. We summed country-level findings to produce PAFs for each risk factor and regional estimates for sub-Saharan Africa and South Asia.ResultsForty-four potential sPTB risk factors were identified. and the final analysis included twenty-four risk factors with evidence of significant associations with sPTB. A second model with three additional risk factors with borderline insignificant associations was also run. Taken together, the twenty-four risk factors had a total PAF of 73% for all 81 countries and 77% and 72% of sPTB in sub-Saharan Africa and South Asia, respectively. For all countries, maternal undernutrition had the highest PAF (17.5%), followed by maternal infections (16.6%), environmental exposures (16%) and pregnancy history (8.7%).ConclusionsWhile multiple risk factors contribute to sPTB, no single risk factor addresses a predominant fraction, and 27% of spontaneous preterm births are not associated with risk factors that we identified. Despite the significant role of preterm birth in child survival, there are major data gaps in LMIC settings. Furthermore, there is a paucity of evidence for effective interventions to prevent preterm birth. Preventing sPTB requires understanding underlying mechanisms leading to sPTB in different populations, and the identification/implementation of effective interventions.

Prediction of Spontaneous Preterm Birth in Women with Ischemic-Cervical Insufficiency Corrected with the Pessary

Objective: to develop a model for prediction of spontaneous preterm birth (SPB) in women with ischemic-cervical insufficiency (ICI), identified and corrected with the pessary at the term 19-23/6 weeks of gestation.Material and methods: 90 female patients with ischemic-cervical insufficiency, identified at 19-23/6 weeks of gestation (group 1 (n = 34) included women who gave preterm birth, group 2 (n = 56) were women who gave term birth), have been examined.Results. The risk factors for SPB in the patients with ICI vary depending on the gestational age. The significant risk factors before the detection of ICI are: miscarriage; absence of term birth in the past history of multiparous women; violation of the vaginal microflora; transmitted urogenital infections. The risk factors for SPB at the time of the ICI verification: «sludge» in the lower pole of the fetal bladder; symptomatic variant of the course of ICI; low values of fluorescence protein in the cervical mucus. The risk factors for SPB after the performed correction of the ICI with the pessary are: high UCA values at 24 and 28 weeks of gestation; «sludge» in the amniotic fluid; tone of the lower segment of the uterus; reduced length of the closed part of the cervical cervix; pessary displacement. A dynamic prognosis will make it possible to identify the risk group for SPB at each stage of the management of preg-nant women, which will improve perinatal outcomes.Conclusion. The proposed prognostic model (AUC = 0.935; Se = 76.5%; Sp = 96.4 %; 95% CI 0.86-0.98; p = 0.0001) has a high diagnostic efficiency of 90.3 %.

Prolonged Second Stage in the First Pregnancy and Risk of Subsequent Spontaneous Preterm Birth [30R

INTRODUCTION: Preterm birth (PTB) is the leading cause of neonatal morbidity/mortality. Although some risk factors for spontaneous PTB (sPTB) are known, sPTB often occurs without identifiable risk factors. A prolonged second stage may increase sPTB risk via mechanical trauma that disrupts cervical integrity. This study examines the association between second stage length and subsequent sPTB. METHODS: This retrospective study included women with two consecutive singleton deliveries at one institution from 07/2012-06/2018, with the first delivery occurring at term. Prolonged second stage (PSS) was defined as 4 hours or more, based on this cohort's 75th percentile and on national recommendations. Very prolonged second stage (VPSS) was defined as 7 hours or more, based on this cohort's 95th percentile. The primary outcome was subsequent sPTB before 37 weeks. Fisher exact test, Kruskal-Wallis test, and logistic regression were used for statistical analysis. RESULTS: Among 1,032 included women, the overall subsequent sPTB rate was 3.1%. Identified in 24.4%, PSS was not associated with increased rate of sPTB (4.4% with PSS vs 2.7% without PSS, p=0.21). Identified in 4.3%, VPSS was associated with a higher rate of sPTB (9.1% with VPSS vs 2.8% without VPSS, p=0.04, OR 3.4, 95% CI 1.1-10.2). CONCLUSION: When dichotomized using the nationally-accepted cutoff of 4 hours, prior second stage length was not associated with subsequent sPTB. However, there was an association between increased risk of sPTB and second stage length when using a higher cutoff of 7 hours. Because that population's sample size was small, larger studies are required to confirm this association.

Deployment and Preterm Birth Among US Army Soldiers.

With increasing integration of women into combat roles in the US military, it is critical to determine whether deployment, which entails unique stressors and exposures, is associated with adverse reproductive outcomes. Few studies have examined whether deployment increases the risk of preterm birth; no studies (to our knowledge) have examined a recent cohort of servicewomen. We therefore used linked medical and administrative data from the Stanford Military Data Repository for all US Army soldiers with deliveries between 2011 and 2014 to estimate the associations of prior deployment, recency of deployment, and posttraumatic stress disorder with spontaneous preterm birth (SPB), adjusting for sociodemographic, military-service, and health-related factors. Of 12,877 deliveries, 6.1% were SPBs. The prevalence was doubled (11.7%) among soldiers who delivered within 6 months of their return from deployment. Multivariable discrete-time logistic regression models indicated that delivering within 6 months of return from deployment was strongly associated with SPB (adjusted odds ratio = 2.1, 95% confidence interval: 1.5, 2.9). Neither multiple past deployments nor posttraumatic stress disorder was significantly associated with SPB. Within this cohort, timing of pregnancy in relation to deployment was identified as a novel risk factor for SPB. Increased focus on servicewomen's pregnancy timing and predeployment access to reproductive counseling and effective contraception is warranted.

Maternal risk factors for preterm birth: a country-based population analysis

ObjectiveThe aim of this study was to identify maternal risk factors for spontaneous preterm birth (PTB) compared to delivery at term, in order to recognize high risk women and to provide a global overview of the Italian situation. Study designA multicenter, observational and retrospective, cross-sectional study was designed. The study population comprised 7634 women recruited in 9 different University Maternity Hospitals in Italy. The main criteria for inclusion were: women having had vaginal preterm or term spontaneous delivery in each participating centre during the study period. The records related to deliveries occurring between April and December 2008. A multivariable logistic regression was employed to identify independent predictors of spontaneous preterm birth. Odds ratios (ORs) and 95% confidence intervals (95% CI) were reported with two-tailed probability (p) values. Statistical calculations were carried out using SAS version 9.1. A two-tailed p-value of 0.05 was used to define statistical significant results. ResultsA significant increased risk of PTB was found in women with BMI>25 (OR=1.662; 95% CI=1.033–2.676; p-value=0.0365) and in women employed in heavy work (OR=1.947; 95% CI=1.182–3.207; p-value=0.0089). Moreover there was a significant association between PTB and previous reproductive history. In fact a history of previous abortion (OR=1.954; 95% CI=1.162–3.285; p-value=0.0116) or previous cesarean section (OR=2.904; 95% CI=1.066–7.910; p-value=0.0371) was positively correlated to the increased risk of PTB and an important statistically significant association was calculated between PTB and previous pre-term delivery (OR=3.412; 95% CI=1.342–8.676; p-value=0.0099). All the other covariates examined as potential risk factors for PTB were not found to be statistically significantly related (p-value>0.05). ConclusionsThe present study, applied to a substantial sample of Italian population, demonstrates that there are peculiar risk factors for spontaneous PTB in the Italian population examined. It shows an association between preterm delivery and certain maternal factors as: BMI, employment, previous abortions, previous PTBs and previous cesarean section.