Association between maternal smoke exposure and congenital heart defects from a case–control study in China

There is a gap in knowledge how maternal exposure to environmental tobacco smoke (ETS) is associated with offspring congenital heart defects (CHDs). In this case–control study, we collected data on 749 fetuses with CHDs and 880 fetuses without any congenital anomalies to examine the association of maternal ETS with fetal CHDs and the potentially moderating effect by maternal hazardous and noxious substances (HNS), periconceptional folate intake and paternal smoking. Maternal exposure to ETS in first trimester was associated with increased risk of CHDs in a dose–response gradient, with the AORs (95% CI) were1.38 (1.00–1.92), 1.60 (1.07–2.41), and 4.94 (2.43–10.05) for ETS