Evaluation of the association between maternal folic acid supplementation and the risk of congenital heart disease: a systematic review and meta-analysis

Background Folic acid (FA), as a synthetic form of folate, has been widely used for dietary supplementation in pregnant women. The preventive effect of FA supplementation on the occurrence and recurrence of fetal neural tube defects (NTD) has been confirmed. Incidence of congenital heart diseases (CHD), however, has been parallelly increasing worldwide. The present study aimed to evaluate whether FA supplementation is associated with a decreased risk of CHD. Methods We searched the literature using PubMed, Web of Science and Google Scholar, for the peer-reviewed studies which reported CHD and FA and followed with a meta-analysis. The study-specific relative risks were used as summary statistics for the association between maternal FA supplementation and CHD risk. Cochran's Q and I-2 statistics were used to test for the heterogeneity. Results Maternal FA supplementation was found to be associated with a decreased risk of CHD (OR = 0.82, 95% CI: 0.72-0.94). However, the heterogeneity of the association was high (P < 0.001, I-2 = 92.7%). FA supplementation within 1 month before and after pregnancy correlated positively with CHD (OR 1.10, 95%CI 0.99-1.23), and high-dose FA intake is positively associated with atrial septal defect (OR 1.23, 95%CI 0.64-2.34). Pregnant women with irrational FA use may be at increased risk for CHD. Conclusions Data from the present study indicate that the heterogeneity of the association between maternal FA supplementation and CHD is high and suggest that the real relationship between maternal FA supplementation and CHD may need to be further investigated with well-designed clinical studies and biological experiments.

Automated summary

The study found that maternal FA supplementation is associated with a decreased risk of CHD. However, there is high heterogeneity in the association between FA supplementation and CHD, and high-dose FA intake may be positively associated with atrial septal defect.