A Comprehensive Assessment of the Associations Between Season of Conception and Birth Defects, Texas, 1999-2015

Temporal Trends of Neonatal Surgical Conditions in Texas and Accessibility to Pediatric Surgical Care

INTRODUCTION

Texas consistently accounts for approximately 10% of annual national births, the second highest of all US states. This temporal study aimed to evaluate incidences of neonatal surgical conditions across Texas and to delineate regional pediatric surgeon accessibility.

METHODS

The Texas Birth Defects Registry was queried from 1999 to 2018, based on 11 well-established regions. Nine disorders (30,476 patients) were identified as being within the operative scope of pediatric surgeons: biliary atresia (BA), pyloric stenosis (PS), Hirschsprung's disease, stenosis/atresia of large intestine/rectum/anus, stenosis/atresia of small intestine, tracheoesophageal fistula/esophageal atresia, gastroschisis, omphalocele, and congenital diaphragmatic hernia. Annual and regional incidences were compared (/10,000 births). Statewide pediatric surgeons were identified through the American Pediatric Surgical Association directory. Regional incidences of neonatal disorder per surgeon were evaluated from 2010 to 2018 as a surrogate for provider disparity.

RESULTS

PS demonstrated the highest incidence (14.405/10,000), while BA had the lowest (0.707/10,000). Overall, incidences of PS and BA decreased significantly, while incidences of Hirschsprung's disease and small intestine increased. Other diagnoses remained stable. Regions 2 (48.24/10,000) and 11 (47.79/10,000) had the highest incidence of neonatal conditions; Region 6 had the lowest (34.68/10,000). Three rural regions (#2, 4, 9) lacked pediatric surgeons from 2010 to 2018. Of regions with at least one surgeon, historically underserved regions (#10, 11) along the Texas-Mexico border consistently had the highest defect per surgeon rates.

CONCLUSIONS

There are temporal and regional differences in incidences of neonatal conditions treated by pediatric surgeons across Texas. Improving access to neonatal care is a complex issue that necessitates collaborative efforts between state legislatures, health systems, and providers.

Maternal physical activity, sitting, and risk of non-cardiac birth defects

BACKGROUND

The relationship between maternal physical activity (PA)/sitting and birth defects is largely unexplored. We examined whether pre-pregnancy PA/sitting were associated with having a pregnancy affected by a birth defect.

METHODS

We used data from two United States population-based case-control studies: 2008-2011 deliveries from the National Birth Defects Prevention Study (NBDPS; 9 states) and 2014-2018 deliveries from the Birth Defects Study To Evaluate Pregnancy exposureS (BD-STEPS; 7 states). Cases with one of 12 non-cardiac birth defects (n = 3798) were identified through population-based registries. Controls (n = 2682) were live-born infants without major birth defects randomly sampled using vital/hospital records. Mothers self-reported pre-pregnancy PA/sitting. Unconditional logistic regression models estimated associations between PA/sitting categories and the 12 birth defects.

RESULTS

Mothers engaging in pre-pregnancy PA was associated with a reduced odds of five (spina bifida, cleft palate, anorectal atresia, hypospadias, transverse limb deficiency) and a higher odds of two (anencephaly, gastroschisis) birth defects. Mothers spending less time sitting in pre-pregnancy was associated with a reduced odds of two (anorectal atresia, hypospadias) and a higher odds of one (cleft lip with or without cleft palate) birth defect.

CONCLUSIONS

Reasonable next steps include replication of these findings, improved exposure assessment, and elucidation of biologic mechanisms.

IMPACT

Using data from two population-based case-control studies, we found that mothers engaging in different types of physical activity in the 3 months before pregnancy had an infant with a reduced odds of five and a higher odds of two birth defects. Mothers spending less time sitting in the 3 months before pregnancy had an infant with a reduced odds of two and a higher odds of one birth defect. Clarification and confirmation from additional studies are needed using more precise exposure measures, distinguishing occupational from leisure-time physical activity, and elucidation of mechanisms supporting these associations.

Association between season of conception, month of conception with preterm birth in China: a population-based retrospective cohort study

BACKGROUND

Seasonal patterns of preterm birth were identified in previous studies, but the effect of conception season on preterm birth has not been extensively studied. Based on the notion that the etiological roots of preterm birth lie in the beginning of pregnancy, we did a population-based retrospective cohort study in Southwest China to examine the effects of season of conception and month of conception on preterm birth.

METHODS

We did a population-based retrospective cohort study in women (aged 18-49) who participated in the NFPHEP from 2010 to 2018, and had a singleton livebirth in southwest China. According to the time of the last menstruation reported by the participants, month of conception and season of conception were then ascertained. We used multivariate log-binomial model to adjust the potential risk factors for preterm birth and obtained adjusted risk ratio (aRR) and 95% confidence intervals (95%CI) for conception season, conception month and preterm birth.

RESULTS

Among 194 028 participants, 15 034 women had preterm birth. Compared with pregnancies that were conceived in the summer, pregnancies that were conceived in the spring, autumn and winter had the higher risk of preterm birth (Spring: aRR = 1.10, 95% CI: 1.04-1.15; Autumn: aRR = 1.14, 95% CI: 1.09-1.20; Winter: aRR = 1.28, 95% CI: 1.22-1.34) and also had a higher risk of early preterm birth (Spring: aRR = 1.09, 95% CI: 1.01-1.18; Autumn: aRR = 1.09, 95% CI: 1.01-1.19; Winter: aRR = 1.16, 95% CI: 1.08-1.25). Pregnancies in December, and January had a higher risk of preterm birth and early preterm birth than pregnancies that were conceived in July.

CONCLUSIONS

Our study found that preterm birth was significantly related to season of conception. Preterm and early preterm birth rates were the highest among pregnancies that were conceived in winter, and the lowest among pregnancies in summer.

Urban-rural residence and birth defects prevalence in Texas: a phenome-wide association study

BACKGROUND

Some assessments indicate the prevalence of certain birth defects varies by urban-rural status. We evaluated associations between urban-rural residence and a spectrum of birth defects, using a phenome-wide association study approach in Texas, a state with large urban centers and expansive rural areas.

METHODS

Data for birth defects and livebirths during 1999-2015 were obtained from the Texas Birth Defects Registry and the Center for Health Statistics. Maternal residence was classified as urban or rural, and prevalence ratios (PR) and 95% confidence intervals (CI) were calculated for any defect and 140 specific defects by Poisson regression.

RESULTS

Overall, birth defects were less frequent in rural compared to urban counties (PR = 0.88, 95% CI: 0.87-0.89). Twelve specific defects were less prevalent in rural counties, including ventricular septal defects (VSDs; PR = 0.76, 95% CI: 0.73-0.79) and hypospadias (PR = 0.86, 95% CI: 0.82-0.89). For some birth defects, including VSDs, there was evidence of decreasing prevalence with decreasing population size.

CONCLUSIONS

In our large population-based assessment, we demonstrated that several birth defects were less prevalent in rural counties, suggesting that characteristics of urban settings may be relevant to their etiologies, diagnosis, or surveillance. Further research is needed to identify specific exposures underlying these associations.

IMPACT

There are few studies of birth defects prevalence in urban versus rural settings. To address this, we investigated a comprehensive range of birth defects, including several rare defects that have not been previously studied, in a large and diverse population. We identified 12 structural birth defects that were less prevalent in rural areas. Findings suggest possible differential exposures among urban and rural women, and/or possible underdiagnosis of certain birth defects in rural areas. Findings highlight the need for further study of geographically referenced risk factors for birth defects, and of the completeness of birth defects ascertainment in rural areas.

Exposure to air pollution is associated with congenital anomalies in the population born by in vitro fertilization

BACKGROUND

Congenital anomalies (CAs) are the leading causes for children's disabilities and mortalities worldwide. The associations between air pollution and CAs are not fully characterized in fetuses born by in vitro fertilization (IVF) who are at high risk of congenital anomalies.

METHODS

We conducted a cross-sectional study including 16,971 IVF cycles from three hospitals in Hebei Province, China, 2014-2019. Air quality data was obtained from 149 air monitoring stations. Individual average daily concentrations of PM_2.5, PM₁₀, NO₂, SO₂, CO, and O₃ were estimated by spatiotemporal kriging method. Exposure windows were divided into 5: preantral follicle period, antral follicle period, germinal period, embryonic period and early fetal period. Logistic generalized estimating equations were used to estimate the associations between air pollutants and overall or organ-system specific congenital anomalies. Negative control exposure method was used to detect and reduce bias of estimation.

RESULTS

We found increasing levels of PM_2.5 and PM₁₀ were associated with higher risk of overall congenital anomalies during early fetal period, equating gestation 10-12 weeks (OR: 1.05, 95% CI: 1.02-1.09, p = 0.013 for a 10 μg/m³ increase of PM_2.5; OR: 1.03, 95% CI: 1.01-1.06, p = 0.021 for a 10 μg/m³ increase of PM₁₀). Cleft lip and cleft palate were associated with PM₁₀ in germinal period and early fetal period. The CAs of eye, ear, face and neck were related to CO in preantral follicle stage. We did not find an association between chromosome abnormalities and air pollution exposure.

CONCLUSIONS

We concluded that ambient air pollution was a risk factor for congenital anomalies in the fetuses conceived through IVF, especially exposure in early fetal period.