J Pediatr. 2021 Sep 8:S0022-3476(21)00877-5. doi: 10.1016/j.jpeds.2021.09.005. Online ahead of print.
OBJECTIVES: To assess associations between maternal smoking and congenital heart defects (CHDs) in offspring.
STUDY DESIGN: We performed a retrospective case-control study using data for cases of CHD (n=8,339) and non-malformed controls (n=11,020) children from all years (1997-2011) of the National Birth Defects Prevention Study. Maternal self-reported smoking one month before through three months after conception was evaluated as a binary (none, any) and categorical (light, medium, heavy) exposure. Multivariable logistic regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals. Stratified analyses were performed for septal defects according to maternal age, pre-pregnancy body mass index, and maternal race/ethnicity.
RESULTS: Multiple CHDs displayed modest associations with any level of maternal periconceptional smoking independent of potential confounders; the strongest associations were for aggregated septal defects (OR 1.5 [1.3-1.7]), tricuspid atresia (OR 1.7 [1.0-2.7]), and double outlet right ventricle (DORV) (1.5 [1.1-2.1]). TA and DORV also displayed dose-response relationships. Among heavy smokers, the highest odds were again observed for TA (aOR 3.0 [1.5-6.1]) and DORV (aOR 1.5 [1.1-2.2]). Heavy smokers ≥35 years old more frequently had a child with a septal defect when compared with similarly aged non-smokers (aOR 2.3 [1.4-3.9]).
CONCLUSIONS: Maternal periconceptional smoking is most strongly associated with septal defects, TA and DORV; the risk for septal defects is modified by maternal age.