Folic acid, AKA folate (folic acid) (vit B9), is recommended for all women wanting to get pregnant -- 0.4mg (400mcg) daily, which is important for preventing birth defects like spina bifida. Women w/ a hx these disorders should take 10x that amt daily -- 4mg (4000mcg) through the 3rd month of pregnancy. It won't affect fertility, chances of conception/twins, or periods. Can help with anemia.