Give me afucking break. You sample vitamins. We have human history on our side. NTDs do occur, so does mental retardation, so do club feet, lazy eyes, etc.
The addition of folate, ANY FOLATE helps. Any monkey can by folate at grocery store. There is no evidence based medical study that compares a woman with a healthy diet, who takes care of herself v a woman with a healthy diet who takes care of herself and takes a vitamin. The FDA regulates dietary supplements as foods, and not as drugs. The FDA does not pre-approve dietary supplements on their safety and efficacy, unlike drugs. In contrast, the FDA can only go after dietary supplement manufacturers after they have put unsafe products on the market.
Do you know what efficacy means?