Periconceptional folic acid supplementation and sex difference in prevention of neural tube defects and their subtypes in China: results from a large prospective cohort study.

FA supplementation successfully reduces the prevalence of NTDs in both male and female infants, although we found a significantly greater decrease in anencephaly and total NTDs in females than in males. How the protective effects of FA supplementation affect the sexes differently needs to be studied further.