What nutrient is primarily provided by prenatal vitamins to prevent neural tube defects?

Folic acid is the key nutrient provided by prenatal vitamins that plays a crucial role in preventing neural tube defects during early pregnancy. Neural tube defects, such as spina bifida and anencephaly, occur when the neural tube, which eventually develops into the spinal cord and brain, does not close properly.

Folic acid, also known as vitamin B9, is essential in the formation and closure of the neural tube, which happens in the first weeks of gestation—often before a woman even realizes she is pregnant. Adequate intake of folic acid before conception and during the early stages of pregnancy significantly reduces the risk of these defects. This is why healthcare providers strongly recommend that women who are planning to conceive or who are in the early stages of pregnancy take prenatal vitamins that contain folic acid.

While other nutrients like calcium, vitamin D, and iron are important during pregnancy for various bodily functions and fetal development, they do not specifically target the prevention of neural tube defects as folic acid does. Therefore, the emphasis on folic acid supplementation is paramount in prenatal care.