• Pre-conceptional PM 2.5 exposure linked to overall and specific birth defects. • Pre-conceptional PM 10 exposure linked to orofacial defects. • Exposure to PM 2.5 and PM 10 during 0–8 gestational weeks increased overall risk pf birth defect. • Perinatal exposure to SO 2 , CO, NO 2 , or O 3 were not associated with any birth defects. • Pre-conceptional PM 2.5 and PM 10 exposure were observed sex-specific effects on birth defects. Maternal exposure to ambient air pollution has been linked to birth defects. However, the relationship between maternal exposure to each air pollutant and live birth defects exhibits significant heterogeneity across different regions and exposure time windows. Here, this study enrolled 190,372 pregnant women who delivered between 2015 and 2020 from two Shanghai hospitals and examined the effects of exposure to 6 types of ambient air pollutants, including particulate matter with a diameter of 2.5 μm or less (PM 2.5 ), particulate matter with a diameter of 10 μm or less (PM 10 ), sulfur dioxide (SO 2 ), carbon monoxide (CO), nitrogen dioxide (NO 2 ) and ozone (O 3 ), on the prevalence of different kinds of live birth defects throughout 3 periods: 3 months before conception, the 1 st and 2 nd trimester systematically. Significant associations were all confined to the preconception 3-month window. An IQR increase in PM 2.5 exposure was linked to any live birth defect, including cardiovascular, orofacial, urogenital, musculoskeletal and others abnormalities. PM 10 was associated with orofacial and other abnormalities. No associations were found for SO 2 , CO, NO 2 , or O 3 in any window. Though the 1 st trimester were not found to be the sensitive window, week-specific effects curves indicated that any live birth defect was found to associated with exposure to PM 2.5 and PM 10 during significant vulnerable window specifically around 0–8 weeks of gestation. Furthermore, sex-stratified results showed maternal PM 2.5 exposure linked to any defect in males and PM 10 exposure linked to orofacial defects in females during preconception period. In summary, maternal PM 2.5 and PM 10 exposure during the 3 months before conception increases the risk of live birth defects, with sex-specific susceptibility, highlighting this window for targeted air-quality interventions.
Chen et al. (Sun,) studied this question.