Objective

To determine the effects of maternal periconceptional supplementation with folic acid or multiple micronutrients containing folic acid on the prevention of fetal congenital heart defects (CHDs).

Study design

Data were drawn from a Prenatal Health Care System and a Birth Defects Surveillance System in a district of Beijing, China. A total of 63 969 singleton births, live or stillborn, 308 CHDs among them, during 2013 to 2018 were included. Associations between different patterns of supplementation and risk for total CHDs or main types of CHDs were evaluated with risk ratios (RRs).

Results

For folic acid or multiple micronutrients containing folic acid users compared with nonusers, the adjusted RRs (ARRs) for total CHDs, critical CHD, and ventricular septal defect (VSD) were 0.60 (95% CI, 0.44-0.83), 0.41 (95% CI, 0.26-0.67), and 0.47 (95% CI, 0.30-0.74), respectively. When we compared multiple micronutrients containing folic acid users with folic acid users, the ARRs were 0.84 (95% CI, 0.66-1.09), 0.64 (95% CI, 0.41-1.00), and 0.94 (95% CI, 0.63-1.41) for total CHDs, critical CHD, and VSD, respectively. We also found that, compared with supplementation initiated after conception, supplementation initiated before conception was associated with a lower risk for CHDs: the ARRs were 0.68 (95% CI, 0.48-0.95) for total CHDs and 0.26 (95% CI, 0.10-0.71) for critical CHD, but 1.08 (95% CI, 0.63-1.83) for VSD.

Conclusions

Maternal periconceptional supplementation with folic acid or multiple micronutrients containing folic acid seems to decrease the risk for CHDs, especially critical CHD, in offspring. Supplementation confers a greater protective effect when it is initiated before conception. We did not find any difference between folic acid and multiple micronutrients containing folic acid in terms of preventing CHDs.