Dose of folic acid for women at increased risk of Neural tube defects preconceptionally is

Most women at increased risk for NTDs benefit from 4 mg folic acid taken daily before conception and through the first trimester. This is paicularly impoant if a woman has one or more prior affected children or if either the pregnant woman or her paner has such a defect. Folic acid supplementation may not decrease the risk for NTDs in those with valproic acid exposure, pregestational diabetes, first-trimester fever or hot tub exposure, or defects associated with a genetic syndrome (Ref: William's Obstetrics; 25th edition)