Increased Risk Of Preterm Birth Research Articles

The relationship between maternal environmental temperature exposure and preterm birth: A Risk prediction based on machine learning

Global warming and the risk of preterm birth are both major factors that impact population health. This study investigated the impact of environmental temperature during different stages of pregnancy on the probability of preterm birth (PTB) in Wuhan, China through 2014 to 2016. The results revealed that temperature exposure throughout the entire pregnancy exhibited a U-shaped relationship with the risk of PTB; when temperature exposure during the entire pregnancy was below 14 °C or above 20 °C, the risk of PTB increased. Early pregnancy exposure to temperatures below 7 °C or above 22 °C, and late pregnancy exposure to temperatures below 7 °C or above 26 °C, were associated with an increased risk of PTB. Additionally, elevated PM2.5 exposure increased PTB risk, while O3 exposure exhibited a U-shaped relationship with preterm birth. Compared to non-high-risk pregnancies, high-risk pregnancies exhibited a higher risk of preterm birth across all stages of pregnancy. Notably, when late pregnancy temperature exposure exceeded 28 °C, the risk of PTB rapidly increased for non-high-risk pregnancies. This research has significant implications for improving maternal and new-born health by future sustainable city planning and the optimization of temperature forecast warning systems, particularly under the dual pressures of rapid urbanization and climate change.

Impacts of heat and wildfire on preterm birth

BackgroundClimate change continues to increase the frequency, intensity, and duration of heat events and wildfires, both of which are associated with adverse pregnancy outcomes. Few studies simultaneously evaluated exposures to these increasingly common exposures. ObjectivesWe investigated the relationship between exposure to heat and wildfire smoke and preterm birth (PTB). MethodsIn this time-stratified case-crossover study, participants consisted of 85,806 California singleton PTBs (20–36 gestational weeks) from May through October of 2015–2019. Birthing parent ZIP codes were linked to high-resolution daily weather, PM2.5 from wildfire smoke, and ambient air pollution data. Heat day was defined as a day with apparent temperature >98th percentile within each ZIP code and heat wave was defined as ≥2 consecutive heat days. Wildfire-smoke day was defined as a day with any exposure to wildfire-smoke PM2.5. Conditional logistic regression was used to calculate the odds ratio (OR) and 95% confidence intervals (CI) comparing exposures during a hazard period (lags 0–6) compared to control periods. Analyses were adjusted for relative humidity, fine particles, and ozone. ResultsWildfire-smoke days were associated with 3.0% increased odds of PTB (ORlag0: 1.03, CI: 1.00–1.05). Compared with white participants, associations appeared stronger among Black, Hispanic, Asian, and American Indians/Alaskan Native participants. Heatwave days (ORlag2: 1.07, CI: 1.02–1.13) were positively associated with PTB, with stronger associations among those simultaneously exposed to wildfire smoke days (ORlag2: 1.19, CI: 1.11–1.27). Similar findings were observed for heat days and when other temperature metrics (e.g., maximum, minimum) were used. DiscussionHeat and wildfire increased PTB risk with evidence of synergism. As the occurrence and co-occurrence of these events increase, exposure reduction among pregnant people is critical, especially among racial/ethnic minorities.

Analysis of Vaginal Microbiota Variations in the Third Trimester of Pregnancy and Their Correlation with Preterm Birth: A Case-Control Study.

This study conducted a detailed analysis of the vaginal microbiota in pregnant women to explore its correlation with preterm birth (PTB) outcomes. The primary objective was to identify microbial variations associated with increased PTB risk. Secondary objectives included investigating how changes in microbial composition relate to the local immune environment and PTB. Utilizing a retrospective case-control design, the study involved pregnant women with liveborn infants between 2019 and 2023. In total, 89 women who delivered preterm and 106 term deliveries were included. Data collection focused on third-trimester vaginal cultures. Statistically significant differences were observed between the preterm and full-term groups in several areas. The median white blood cell count (10.2 × 103/mm3 vs. 7.6 × 103/mm3, p = 0.009) and neutrophil count (7.2 × 103/mm3 vs. 5.1 × 103/mm3, p < 0.001) were higher in the preterm group. Vaginal pH was also elevated in preterm births (5.6 vs. 4.4, p < 0.001), with a higher prevalence of bacterial vaginosis (29.2% vs. 12.3%, p = 0.001) as indicated by the Nugent Score. The study noted a significant association of PTB with the presence of Candida spp. (OR = 1.84, p = 0.018), Gardnerella vaginalis (OR = 2.29, p = 0.003), Mycoplasma hominis (OR = 1.97, p = 0.007), and Ureaplasma urealyticum (OR = 2.43, p = 0.001). Conversely, a reduction in Lactobacillus spp. correlated with a decreased PTB risk (OR = 0.46, p = 0.001). The study provides compelling evidence that specific vaginal microbiota components, particularly certain pathogenic bacteria and an altered Lactobacillus profile, are significantly associated with PTB risk. These findings highlight the potential of targeting microbial factors in strategies aimed at reducing PTB rates. Further research is necessary to fully understand the complex interplay between microbial dynamics, host immunity, and PTB outcomes.

Assessing the Impact of COVID-19 Vaccination on Preterm Birth: A Systematic Review with Meta-Analysis.

During the coronavirus diseases 2019 (COVID-19) pandemic, the safety and efficacy of vaccination during pregnancy, particularly regarding the risk of preterm birth, have been a subject of concern. This systematic review aims to evaluate the impact of COVID-19 vaccination on preterm birth risk and to inform clinical practice and public health policies. Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a database search included PubMed, Embase, and Scopus, conducted up until October 2023. Inclusion criteria focused on studies that examined COVID-19 vaccination during pregnancy and its correlation with preterm birth, defined as a birth before 37 weeks of gestation. Six studies met these criteria, encompassing 35,612 patients. A quality assessment was performed using the Newcastle-Ottawa Scale and the Cochrane Collaboration's tool, with the risk of bias evaluated via a funnel plot analysis and an Egger's regression test. The studies demonstrated geographical diversity, mainly from Israel, Romania, and the United States, with a blend of prospective and retrospective designs. The patient cohort's mean age was 31.2 years, with common comorbidities such as gestational diabetes and obesity affecting 9.85% of the total population. The vaccination types varied across the studies, with BNT162b2 being the most used. The results indicated a low heterogeneity among the included studies, evidenced by a Cochran's Q statistic of 2.10 and an I2 statistic of 13%. The meta-analysis yielded a pooled odds ratio (OR) for a preterm birth risk post-vaccination of approximately 1.03 (95% CI: 0.82-1.30), suggesting no significant increase in preterm birth risk was associated with COVID-19 vaccination. Notable findings included a low preterm birth rate (as low as 0.6% and up to 6.1%) with minimal differences in neonatal outcomes, such as birth weight and APGAR (appearance, pulse, grimace, activity, and respiration) scores between vaccinated and unvaccinated groups. This study concludes that a COVID-19 vaccination during pregnancy does not significantly increase the risk of preterm birth. These findings are crucial for reassuring healthcare providers and pregnant women about the safety of COVID-19 vaccines and supporting their use in public health strategies during the pandemic.

Associations between pregnancy glucose measurements and risk of preterm birth: a retrospective cohort study of commercially insured women in the United States from 2003 to 2021

To investigate associations between glucose measurements during pregnancy and risk of preterm birth (PTB). Retrospective cohort study of commercially insured women with singleton live births in the United States from 2003 to 2021 using longitudinal medical claims, socioeconomic data, and eight glucose results from different fasting and post-load tests performed between 24 and 28 weeks of gestation for gestational diabetes screening. Risk ratios of PTB (<37 weeks) were estimated via Poisson regression for z-standardized glucose measures. Non-linear relationships for continuous glucose measures were examined via generalized additive models. Elevations in all eight glucose measures were associated with increased risk (adjusted risk ratio point estimates: 1.05-1.19) of PTB for 196,377 women with non-fasting 50-gglucose challenge test (one glucose result), 31,522 women with complete 100-g, 3-hour fasting oral glucose tolerance test (OGTT) results (four glucose results), and 10,978 women with complete 75-g, 2-hour fasting OGTT results (three glucose results). Associations were consistent after adjusting for and stratifying by sociodemographic and clinical factors. Substantial non-linear relationships (U-, J-, and S-shaped) were observed between several glucose measurements and PTB. Elevations in various glucose measures were linearly and non-linearly associated with increased PTB risk, even before diagnostic thresholds for gestational diabetes.

Risk of pre-term birth as a function of sleep quality and obesity: prospective analysis in a large Prematurity Research Cohort.

To investigate whether poor sleep quality is associated with pre-term birth (PTB) risk, overall and independent of sleep apnea and habitual snoring. We used longitudinal data from the Washington University Prematurity Research Cohort to investigate the association between poor sleep quality (defined as a Pittsburgh Sleep Quality Index > 5) and PTB, overall and independent of sleep apnea and snoring (defined by the Berlin questionnaire and prior sleep clinic attendance). Associations were investigated for sleep quality early and throughout pregnancy. Stratified analyses were performed by factors previously shown to modify associations between sleep and PTB (race, pre-pregnancy obesity). Of the 976 eligible participants, 50.1% experienced poor sleep quality early in pregnancy (<20 completed weeks) and 14.2% delivered pre-term (n = 50 without and 89 with poor sleep quality). In multivariable-adjusted analyses, poor sleep quality early in pregnancy was associated with increased PTB risk (hazard ratio [HR] = 1.48, 95% confidence interval [CI] = 1.02-2.14). This association persisted after further adjustment for sleep apnea and snoring (HR = 1.50, 95% CI = 1.02-2.20) and in analyses stratified by race. It varied, however, by pre-pregnancy obesity. Among individuals without obesity, no association was observed between poor sleep and PTB (HR = 1.08, 95% CI = 0.65-1.79), whereas among those with obesity, a positive association was observed (HR = 2.94, 95% CI = 1.52-5.69, p-interaction = .05). This association was limited to individuals with obesity who experienced poor sleep both earlier and later in pregnancy (HR = 3.94, 95% CI = 1.56-9.99). Our findings suggest that improving sleep quality early in pregnancy may be important for PTB prevention, particularly among individuals with obesity.

Association between maternal family history of hypertension and preterm birth: modification by noise exposure and multivitamin intake

Objective To measure the effect of maternal family history of hypertension on preterm birth (PTB) and to identify factors that modified this association. Methods A case-control study was nested in a prospective cohort of the entire pregnant population in Wuhan, China, from 2011 to 2013. Home-visit interviews were scheduled for all PTBs and their controls, to collect extensive information on maternal exposures to behavioral, environmental, and intergenerational risk factors of PTB. The effects of maternal family history of hypertension on PTB were measured by logistic regression analyses, controlling for potential confounders. Potential effect modifiers were examined using stratified analyses. Results There were 2393 PTBs and 4263 full-term births out of all eligible births. A positive association was observed between maternal family history of hypertension and PTB, after adjusted for potential confounders (adjusted odds ratio: 1.17 [1.03, 1.33]). A higher effect was observed when mothers were exposed to certain noise during pregnancy (adjusted odds ratio: 1.37 [1.14, 1.65]) and/or when they did not take multivitamins during pregnancy (adjusted odds ratio: 1.46 [1.20, 1.78]), whereas, this association was weaker and no longer significant when mothers took multivitamins during pregnancy (adjusted odds ratio: 1.00 [0.84, 1.19]) and/or when they were not exposed to certain noise during pregnancy (adjusted odds ratio: 1.01 [0.85, 1.12]). The modification effect from maternal multivitamin intake was significant on both spontaneous and medically indicated PTBs, and the modification effect from maternal exposure to certain noise was only significant on spontaneous PTB. Conclusions Increased PTB risk was observed for pregnant women with a family history of hypertension in Wuhan, China. This effect was stronger when pregnant women did not take multivitamin and/or exposed to certain noise during pregnancy, than those who took multivitamin and/or unexposed to certain noise.

First Trimester of Pregnancy as the Sensitive Period for the Association between Prenatal Mosquito Coil Smoke Exposure and Preterm Birth.

Mosquito coils are efficient mosquito repellents and mosquito coil smoke (MCS) contributes to indoor air pollution. However, no prior population-based study has investigated whether prenatal MCS exposure is a risk factor for preterm birth (PTB) and whether exposure to MCS in different trimesters of pregnancy is associated with different levels of risk. The sample involved 66,503 mother–child dyads. Logistic regression models were used to examine the relationships between prenatal MCS exposure during different trimesters of pregnancy and PTB. We found that prenatal MCS exposure was associated with a greater likelihood of PTB (OR = 1.12, 95%CI: 1.05–1.20). The prenatal MCS exposure during the first trimester was associated with 1.17 (95%CI: 1.09–1.25) times the odds of being PTB, which was higher than exposure during the second trimester (OR = 1.11, 95%CI: 1.03–1.19) and during the third trimester (OR = 1.08, 95%CI: 1.01–1.16). In the stratified analysis, prenatal MCS exposure significantly increased PTB risk among girls but not among boys. Our results indicated that maternal MCS exposure during pregnancy was associated with PTB and that the first trimester might be the sensitive period. In light of these findings, public health interventions are needed to reduce prenatal exposure to MCS, particularly during the first trimester of pregnancy.

Exposure to Ambient Air Pollutant PM10 in the Second Trimester of Pregnancy Is Associated with Preterm Birth: A Birth-Based Health Information Cohort Study.

Objectives We evaluated the effects of exposure to high concentrations of particulate matter (PM)10 on preterm birth (PTB) and identified a critical concentration of PM10 that could lead to PTB via a birth-based health information cohort study. Methods We conducted a birth-based cohort study consisting of nonanomalous singleton births at 22-42 weeks. PTB was defined as babies born alive before 37 weeks of pregnancy. Pregnancy period exposure averages were estimated for PM10 based on the China National Environmental Monitoring Centre (CNEMC). Pregnant women who lived within 50 km of the monitor station were recruited into this study. Logistic regression analyses were performed to determine the association between PTB and exposure to PM10 at different pregnancy periods with adjustment for confounding factors. Results The relative frequency of PTB was 8.7% in the study cohort of 5,291 singleton live births. A total of 1137 women had a high level of PM10 exposure (≥60 μg/m3) in the second trimester of pregnancy. The average concentrations of PM10 in the first, second, and third trimesters of pregnancy and throughout pregnancy were 53.8 μg/m3, 54.2 μg/m3, 55.6 μg/m3, and 54.3 μg/m3, respectively. The generalized additive model (GAM) analysis showed that there was a nonlinear correlation between PM10 and PTB in the second trimester of pregnancy (P < 0.001). The adjusted odds ratio between PTB and low concentration PM10 exposure (PM10 < 60 μg/m3) in the second trimester of pregnancy was 1.01 (95% CI 0.95-1.05). However, high PM10 exposure (PM10 ≥ 60 μg/m3) in the second trimester of pregnancy had an increased PTB risk even after adjustment for coexisting risk factors with an adjusted odds ratio of 1.78 (95% CI 1.69-1.87), and the incidence of PTB increased with an increase in PM10 exposure. Conclusions Our research discovered that exposure to high levels of PM10 increases the risk of PTB and the second trimester is the most vulnerable gestational period to ambient air pollution exposure. PM10 concentrations more than 60 μg/m3 are detrimental to pregnant women in their second trimester. This study has implications for health informatics-oriented healthcare decision support systems.

Maternal exposures to fine and ultrafine particles and the risk of preterm birth from a retrospective study in Beijing, China

Maternal exposure to fine particulate matter (PM2.5) has been associated with increased risk of preterm birth (PTB), but evidence on particles in smaller sizes and PTB risk remains limited. In this retrospective analysis, we included birth records of 24,001 singleton live births from Haidian Maternal and Child Health Hospital in Beijing, China, 2014–2017. Concurrently, number concentrations of size-fractioned particles in size ranges of 5–560 nm (PNC5–560) and mass concentrations of PM2.5, black carbon (BC) and gaseous pollutants were measured from a fixed-location monitoring station in central Haidian District. Logistic regression models were used to estimate the odds ratio (OR) of air pollutants on PTB risk after controlling for temperature, relative humidity, and individual covariates (e.g., maternal age, ethnicity, gravidity, parity, gestational weight gain, fetal gender, the year and season of conception). Positive matrix factorization models were then used to apportion the sources of PNC5–560. Among the 1062 (4.4%) PTBs, increased PTB risk was observed during the third trimester of pregnancy per 10 μg/m3 increase in PM2.5 [OR = 1.92; 95% Confidence Interval (95% CI): 1.76, 2.09], per 1000 particles/cm3 increase in PNC25–100 (OR = 1.09; 95% CI: 1.03, 1.15) and PNC100–560 (OR = 1.22; 95% CI: 1.05, 1.42). Among the identified sources of PNC5–560, emissions from gasoline and diesel vehicles were significantly associated with increased PTB risk, with ORs of 1.14 (95% CI: 1.01, 1.29) and 1.11 (95% CI: 1.04, 1.18), respectively. Exposures to other traffic-related air pollutants, such as BC and nitrogen dioxide (NO2) were also significantly associated with increased PTB risk. Our findings highlight the importance of traffic emission reduction in urban areas.

Composition of fine particulate matter and risk of preterm birth: A nationwide birth cohort study in 336 Chinese cities

BackgroundPotential hazards of fine particulate matter (PM2.5) constituents on preterm birth (PTB) have rarely been explored in China. ObjectiveTo quantify the associations of PM2.5 constituents with PTB. MethodsThis study was based on a nationwide cohort of 3,723,169 live singleton births delivered between January 2010 and December 2015 in China. We applied satellite-based estimates of 5 PM2.5 constituents (organic carbon; black carbon; sulfate; ammonium; and nitrate). We used Cox proportional hazards regression models adjusted for individual covariates, temperature, humidity, and seasonality to evaluate the associations. ResultsDuring the entire pregnancy, each interquartile range (29 μg/m3) increase in PM2.5 concentrations was associated with a 7% increase in PTB risk [hazard ratio (HR): 1.07; 95% confidence interval (CI): 1.07–1.08). We observed the largest effect estimates on carbonaceous components (HR: 1.09; 95% CI: 1.08–1.10 for organic carbon and black carbon). Early pregnancy appeared to be the critical exposure window for most constituents. Women who were older, exposed to second-hand smoke, overweight or obese before pregnancy, conceived during winter, and living in northern China or rural areas were more susceptible. ConclusionsCarbonaceous components of PM2.5 were associated with higher PTB risk. Findings on characteristics of vulnerability underlined targeted protections on susceptible subgroups.

The impact of cervical conization size with subsequent cervical length changes on preterm birth rates in asymptomatic singleton pregnancies

The study aimed to explore the impact of cervical conization size (CCS) with subsequent cervical length (USCL) changes on preterm birth (PTB) rates in asymptomatic singleton pregnancies as compared to pregnancy outcomes in healthy women with an intact cervix (ICG), and to estimate PTB prevention efficiency in patients with a short cervix. Pregnancy outcomes in populations of similar age, ethnicity, residency, education and harmful habits having undergone cervical conization (CCG) were retrospectively analyzed and compared to ICG and cervical conization sub-populations adjusted by USCL during pregnancy (adequate cervical length vs. a short cervix) and a progesterone-only group (POG) vs. a progesterone-pessary group (PPG). Cervical conization was not associated with an increased PTB risk (CCG vs. ICG) when parameters of CCS and USCL were not adjusted (p = NS). A significantly higher proportion of parous women was observed in the CCG population than in the ICG (p = 0.0019). CCS turned out to be a key PTB risk during pregnancy, the larger CCS being associated with a short cervix (p = 0.0001) and higher PTB risks (p = 0.0001) with a notably increased PTB rate (p = 0.0001) in nulliparous women (p = 0.0022), whereas smaller CCS with adequate cervical length and a lower PTB rate was predominantly observed in women with prior parity. An initial equal USCL size was to be considerably elongated in women with adequate cervical length (p < 0.0001), and shortened in those with a short cervix (p < 0.0001). USCL assessment during pregnancy proved to be the PTB risk-predicting tool, with CCS supplementation apt to increase its diagnostic value. No substantial impact on pregnancy outcomes could be linked to any particular PTB prevention mode (POG or PPV). However, during pregnancy, the USCL changes relating to CCS proved to be more critical in pregnancy outcomes.

Association between Specific PM2.5 Chemical Constituents and Preterm Birth in China: A National Birth Cohort Study

BACKGROUND AND AIM: Studies including ours have linked fine particulate matter (PM2.5) exposure during pregnancy to high risk of preterm birth (PTB). However, the roles of specific PM2.5 chemical constituents remain unclear. This study aimed to examine the associations of exposure to PM2.5 and its main chemical components during pregnancy with the risk of PTB in China. METHODS: We established a birth cohort with 1,280,524 singleton pregnancies who delivered from Dec 1st, 2013 to Nov 30th, 2014 and matched their home address to PM2.5 and its main component mass concentrations which were predicted with Weather Research & Forecasting model (WRF) and the Community Multi-scale Air Quality model (CMAQ). Cox proportional hazard regression models with time varying exposure were used to analyze the associations between PTB and exposure of PM2.5 and its main components, after controlling for individual level covariates. RESULTS:In fully adjusted models, a PM2.5 concentration increase of 10 μg/m3 over the entire pregnancy was significantly associated with increased risk of PTB (hazard ratio [HR], 1.07; 95%CI, 1.06 to 1.07). We also find elemental carbon (EC), organic carbon (OC), Sulfate (SO42-), nitrate (NO3-) and ammonium (NH4+) exposure was associated with increased risk of PTB (HR = 1.21 to 1.76). PM2.5 with higher EC, NH4+ or NO3- fraction, often linked to fossil combustion, exhibited a lower association with preterm birth (P0.001), while PM2.5 with higher OC fraction, often linked to organic compounds, exhibited a higher association with preterm birth (P0.001). CONCLUSIONS:Our findings provide evidence that exposure to PM2.5 components mainly from organic compounds may have predominance in the contributions to increased PTB risk associated with PM2.5 exposure in China. KEYWORDS: Particle components, Birth outcomes, Environmental epidemiology

Antithyroid drug treatment and pregnancy outcomes among women with hyperthyroidism in pregnancy: A Norwegian population-based registry-linkage study

Aims: The aim of this study was two-fold: i) to describe factors associated with antithyroid drug (ATD) treatmentduring gestation among women with hyperthyroidism in pregnancy, ii) to investigate the impact of ATDtreatment during gestation on pregnancy outcomes.Methods: Women with hyperthyroidism in pregnancy and ATD treatments were identified through linkage ofthree national registries (2008-2018): The Medical Birth Registry of Norway, the Norwegian PrescriptionRegistry and the Norwegian Patient Registry. Pregnancies were categorized as ATD treated or untreated basedon filled prescriptions indicating ATD exposure during pregnancy. ATD treatment was examined by trimester(T1, T2/T3) and by substance carbimazole (CMZ), propylthiouracil (PTU) and by both CMZ/PTU. Generalizedestimating equations analysis with a robust variance estimator was used to estimate adjusted odds ratio (aOR)and adjusted standardized mean difference (aSMD) with 95% confidence interval (CI).Results: We identified 1699 pregnancies with hyperthyroidism during gestation. Hyperthyroidism was treatedwith ATD in 44.4% of the pregnancies, while 55.6% were untreated. Pregnant women treated with ATD hadmore often asthma compared to untreated women. Prenatal exposure to CMZ was associated with increased riskof preterm birth (aOR 1.8, 95% CI 1.1-2.8) whereas PTU exposure in the first trimester was associated with anincreased risk of cardiac malformations (aOR 9.0, 95% CI 1.8-44.7). There was no association between ATDtreatment in pregnancy and maternal preeclampsia (aOR 0.8, 95% CI 0.4-1.3) and gestational hypertension (aOR0.9, 95% CI 0.5-1.8).Conclusion: This nationwide registry study found an association between treatment with carbimazole and increasedrisk of preterm birth. Exposure to propylthiouracil in the first trimester was associated with an increasedrisk of cardiac malformations. These findings should be interpreted in light of international findings on the riskof untreated hyperthyroidism and the potential risk of ATD treatment for the mother and child.

916 The association between preterm birth and ultrasound visualization of the cervical gland area

Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality. Yet, transvaginal ultrasound (TVUS) cervical length (CL) screening suboptimally predicts spontaneous PTB (SPTB). Abnormal remodeling of glandular crypts along the cervical canal may contribute to increased PTB risk via premature cervical ripening, which may correspond to no visualizable cervical gland area (CGA) on TVUS (Figure 1). This study aims to determine if no visualizable (“absent”) CGA at CL screening is predictive of PTB. We performed a retrospective cohort study of pregnant women carrying a singleton gestation who had CL screening between 180/7 – 236/7 weeks gestation and delivered a live neonate at a single academic institution between 1/1/18 and 12/31/18. 1000 of the most recent deliveries in 2018 were screened for inclusion. Patients with uterine anomalies, cerclage, suboptimal imaging, or with indicated preterm delivery were excluded. TVUS images were assessed for CL, CGA visualization, and if present, quantitative CGA measurements were performed. The primary outcome was SPTB prior to 37 weeks. Absent and present CGA groups were compared using χ2, Fischer’s exact, T-test, and logistic regression with significance at p<0.05. 784 women were included. Demographic and medical characteristics of the sonographically absent and present CGA groups were similar. The absent CGA group was more likely parous and to receive progesterone supplementation (77 vs 40% and 17 vs 4% respectively, p=0.03). Overall PTB rate was 2.7% and rate of absent CGA was 2.3%. Absent CGA was significantly associated with delivery <37, <34, and <32 weeks (p<0.005) (Table 1). Quantitative CGA width, length, and area did not individually correlate with PTB. A multiple logistic regression model demonstrated 8% improvement for prediction of PTB <37 weeks with the addition of CGA evaluation compared to CL alone (p<0.001). Patients with no visualizable CGA were more likely to experience spontaneous preterm delivery. Assessment of CGA visualization may improve the performance of CL screening for predicting SPTB.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Prenatal Exposure to Specific PM2.5 Chemical Constituents and Preterm Birth in China: A Nationwide Cohort Study.

Exposure to fine particulate matter (PM2.5) during pregnancy has been associated with preterm birth (PTB). However, the existing evidence is inconsistent, and the roles of specific PM2.5 chemical constituents remain unclear. Based on the China Labor and Delivery Survey, we included birth data from 89 hospitals in 25 provinces in mainland China, and conducted a national multicenter cohort study to examine the associations of PM2.5 and its chemical constituents with PTB risk in China. We applied satellite-based models to predict prenatal PM2.5 mass and six main component exposure. Multilevel logistic regression analysis was used to examine the associations, controlling for sociodemographic characteristics, seasonality, and spatial variation. We observe an increased PTB risk with an increase in PM2.5 mass and the most significant association is found during the third trimester when the adjusted odds ratio (OR) per interquartile range increases in PM2.5 total mass is 1.12 (95% confidence Interval, CI: 1.05-1.20). Infants conceived by assisted reproductive technology (ART) show greater PTB risk associated with PM2.5 exposure (OR = 1.33, 95% CI: 1.05-1.69) than those conceived naturally (OR = 1.11, 95% CI: 1.03-1.19). We also find black carbon, sulfate, ammonium and nitrate, often linked to fossil combustion, have comparable or larger estimates of the effect (OR = 1.07-1.14) than PM2.5. Our findings provide evidence that components mainly from fossil fuel combustion may have a perceptible influence on increased PTB risk associated with PM2.5 exposure in China. Additionally, compared to natural conception, conception through ART may be more susceptible to PM2.5 exposure.

Does maternal race or ethnicity modify the association between maternal psychiatric disorders and preterm birth?

PurposePreterm birth risk has been linked to maternal racial and ethnic background, particularly African American heritage; however, the association of maternal race and ethnicity with psychiatric disorders and preterm birth has received relatively limited attention. MethodsThe Consortium on Safe Labor (2002–2008) is a nationwide U.S. cohort study with 223,394 singleton pregnancies. Clinical data were obtained from electronic medical records, including maternal diagnoses of psychiatric disorders. Relative risk (RR) and 95% confidence intervals (CI) were estimated for the association between maternal psychiatric disorders and preterm birth (<37 completed weeks) using log-binomial regression with generalized estimating equations. The interaction effect of maternal psychiatric disorders with race and ethnicity was also evaluated. ResultsNon-Hispanic White (RR, 1.42; 95% CI, 1.35–1.49), Hispanic (RR, 1.44; 95% CI, 1.29–1.60), and non-Hispanic Black (RR, 1.21, 95% CI, 1.13–1.29) women with any psychiatric disorder were at increased risk for delivering preterm infants, compared with women without any psychiatric disorder. However, non-Hispanic Black women with any psychiatric disorder, depression, bipolar disorder, and schizophrenia had a significantly lower increase in preterm birth risk than non-Hispanic White women. ConclusionsDespite the significant association between maternal psychiatric disorders and preterm birth risk, psychiatric disorders did not appear to contribute to racial and ethnic disparities in preterm birth.

Association between Thiopurines Use and Pregnancy Outcomes in Female Patients with Inflammatory Bowel Disease: A Meta-Analysis.

Conflicting data exist regarding the influence of thiopurines exposure on adverse pregnancy outcomes in female patients with inflammatory bowel disease (IBD). The aim of this study was to provide an up-to-date and comprehensive assessment of the safety of thiopurines in pregnant IBD women. All relevant articles reporting pregnancy outcomes in women with IBD received thiopurines during pregnancy were identified from the databases (PubMed, Embase, Cochrane Library, and ClinicalTrials.gov) with the publication data up to April 2020. Data of included studies were extracted to calculate the relative risk (RR) of multiple pregnancy outcomes: congenital malformations, low birth weight (LBW), preterm birth, small for gestational age (SGA), and spontaneous abortion. The meta-analysis was performed using the random-effects model. Eight studies matched with the inclusion criteria and a total of 1201 pregnant IBD women who used thiopurines and 4189 controls comprised of women with IBD received drugs other than thiopurines during pregnancy were included. Statistical analysis results demonstrated that the risk of preterm birth was significantly increased in the thiopurine-exposed group when compared to IBD controls (RR, 1.34; 95% CI, 1.00-1.79; p=0.049; I2 =41%), while no statistically significant difference was observed in the incidence of other adverse pregnancy outcomes. Thiopurines used in women with IBD during pregnancy is not associated with congenital malformations, LBW, SGA, or spontaneous abortion, but appears to have an association with an increased risk of preterm birth.

Communicating with African-American Women Who Have Had a Preterm Birth About Risks for Future Preterm Births

PurposeAfrican-American women are at higher risk of preterm birth (PTB) compared with other racial/ethnic groups in the USA. The primary objective was to evaluate the level of understanding among a group of African-American women concerning risks of PTB in future pregnancies. Secondary objectives were to evaluate how some women obtain information about PTB and to identify ways to raise their awareness.MethodsSix focus groups were conducted in three locations in the USA during 2016 with women (N = 60) who had experienced ≥ 1 PTB (< 37 weeks of gestation) during the last 5 years. The population was geographically, economically, and educationally diverse.ResultsWe observed a tendency to normalize PTB. Knowledge about potential complications for the infant was lacking and birth weight was prioritized over gestational age as an indicator of PTB. Participants were largely unaware of factors associated with increased PTB risk, such as a previous PTB and race/ethnicity. The most trusted information source was the obstetrical care provider, although participants reported relying on mobile apps, websites, and chat rooms. The optimal time to receive information about PTB risk in subsequent pregnancies was identified as the postpartum visit in the provider’s office.ConclusionsAwareness of the risks of recurrent PTB was limited in this diverse population. Educational programs on the late-stage development of neonates may strengthen knowledge on the relationship between gestational age and PTB and associated health/developmental implications. For educational efforts to be successful, a strong nonjudgmental, positive, solutions-oriented message focused on PTB risk factors is crucial.

Association Between Endometriosis and Preterm Birth in Women With Spontaneous Conception or Using Assisted Reproductive Technology: A Systematic Review and Meta-Analysis of Cohort Studies.

To perform a systematic review and meta-analysis to estimate the effect of endometriosis on preterm birth (PB) risk. Searches were conducted in PubMed-MEDLINE, Embase, Scopus, Web of Science, Cochrane Library, Google Scholar, and SciELO for studies published in all languages from inception through April 2017. We included cohort studies evaluating pregnant women with and without endometriosis and conception either by spontaneous conception (SC) or with assisted reproductive technology (ART). Primary outcome was PB (<37 weeks), and secondary outcomes were intrauterine growth restriction (IUGR), low birthweight, small for gestational age (SGA), and birthweight. Pooled odds ratios (ORs) and its 95% confidence interval (CI) were calculated as effects, and random-effects models were used for meta-analyses. Risk of bias was assessed with the Newcastle-Ottawa Scale, and heterogeneity of effects among studies was described with the I2 statistic. We identified 9 cohort studies including a total of 1 496 715 pregnancies (13 798 with endometriosis diagnosis). In women with endometriosis, the PB risk was significantly increased in both SC (OR: 1.59; 95% CI: 1.32-1.90) and ART (OR: 1.43; 95% CI: 1.14-1.79). The SGA risk was increased in women with endometriosis (OR: 1.16; 95% CI: 1.05-1.28), while the IUGR and low birthweight risks and birthweight were not affected by endometriosis. Endometriosis is associated with increased PB risk in both SC and women who obtained pregnancy using ART. Prospective studies evaluating relevant outcomes are needed to confirm these results.