Abstract
Birth defects prevalence may vary seasonally, but previous studies have focused on a few commonly occurring phenotypes. We performed a phenome-wide association study (PheWAS) in order to evaluate the associations between season of conception and a broad range of birth defects. Date of conception was estimated for all livebirths and birth defect cases in Texas from 1999–2015 using data from vital records, provided by the Texas Department of State Health Services Center for Health Statistics. Birth defects diagnoses were obtained from the Texas Birth Defects Registry, a statewide, active surveillance system. We estimated prevalence ratios (PRs) for phenotypes with ≥50 cases according to conception in spring (March-May), summer (June–August) or fall (September–November) relative to winter (December–February), using Poisson regression. Season of conception was associated with 5% of birth defects studied in models adjusted for maternal age, education, race/ethnicity, and number of previous livebirths. Specifically, summer conception was associated with any monitored birth defect (PR 1.03, 95% CI 1.02–1.04) and five specific phenotypes, most notably Hirschsprung disease (PR 1.46, 95% CI 1.22–1.75). These findings suggest that seasonally variable exposures influence the development of several birth defects and may assist in identifying novel environmental risk factors.
Highlights
Birth defects are health problems or abnormal physical changes that can affect any part of the body
Because previous studies have focused on more common birth defects, such as cleft lip and palate, cardiac anomalies, and neural tube defects (NTDs), scant data are available for many anomalies [12,19,20,21]
Understanding how season of conception is associated with birth defects can assist in identifying risk factors and guiding public health practices to educate women in reproductive planning
Summary
Birth defects are health problems or abnormal physical changes that can affect any part of the body (e.g., brain, heart, and intestines). In the United States (US), birth defects affect approximately 3% of births each year and account for 20% of infant deaths [1]. Those who do survive often have life-long medical issues that may impact quality of life. In spite of their prevalence and clinical significance, approximately 60% of these conditions are of unknown etiology [4]. Several environmental exposures have been demonstrated to cause a spectrum of birth defects, including antiepileptic drugs and
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