The association between periconceptional folic acid supplementation and congenital heart defects: a case-control study in China.

Abstract

OBJECTIVE: This study aims to evaluate the association between folic acid (FA) supplementation and congenital heart defects (CHDs). METHODS: This hospital-based case-control study initiated in 2010 in China analyzed 358 cases and 422 controls. The adjusted odds ratio (AOR) calculated using a logistic model was used to assess the association between FA supplementation and CHDs. RESULTS: Compared with a mother who reported no FA supplementation, mothers who reported FA supplementation were less likely to have offspring with isolated CHD(s) (AOR=0.52, 0.34-0.78) and multiple complex conditions (AOR=0.27, 0.14-0.55). However, mothers who reported FA supplementation for less than 1 month regardless of the start time of supplementation, did not have a significantly lower risk of having an offspring with isolated or multiple complex conditions. Mothers who reported FA supplementation for ≧3 months beginning before conception had a significantly lower risk of having children with isolated CHD(s) (AOR=0.31, 0.18-0.54). CONCLUSION: FA-supplementation is associated with reduced risk of CHDs. The earlier FA supplementation begins before pregnancy and the longer supplementation lasts, the lower the risk of CHDs is.