Women's compliance with current folic acid recommendations and achievement of optimal vitamin status for preventing neural tube defects.

The timing of folic acid supplement usage is critical to preventing pregnancies affected by neural tube defects (NTDs) because the neural tube closes by Day 28 post-conception. We investigated compliance of pregnant women with current folic acid recommendations (400 µg/day from preconception to 12 weeks) in relation to achieving a folate status associated with lowest risk of NTDs.