This B-vitamin (B9) protects the baby’s neural tube, which will become the brain and spine. Folate, the naturally occurring form of folic acid, is found in many foods including beans, dark leafy greens, and citrus. It’s most important in the first few weeks, when you may not even know you’re expecting. That’s why it’s key for women of childbearing age to take vitamins. “Women who take folic acid supplements have an up to 80% reduction in neural tube defects,” says Stephen Greenhouse, MD, of Shady Grove Fertility in Fair Oaks, VA; these include serious deformities like spina bifida. The US Preventative Task Force recommends 400 to 800 mcg per day.