Which nutritional supplement is commonly recommended for pregnant women to prevent neural tube defects?

Folic acid is commonly recommended for pregnant women primarily to prevent neural tube defects, which are significant birth defects affecting the brain and spine. These defects occur very early in pregnancy, often before a woman even knows she's pregnant. Folic acid, a B vitamin, plays a crucial role in DNA synthesis and cell division, which are vital processes in fetal development, particularly in the formation of the neural tube.

Research has shown that adequate intake of folic acid before conception and during early pregnancy can significantly reduce the risk of these defects. This is why healthcare providers strongly advise women who are planning to become pregnant to begin taking a folic acid supplement, typically around 400 micrograms daily, in addition to consuming foods rich in folate, such as leafy greens, legumes, and fortified cereals.

While iron, calcium, and vitamin D are important nutrients during pregnancy for overall health and development of the mother and fetus, none of these directly address the prevention of neural tube defects in the same way folic acid does. Iron is essential for preventing anemia, calcium is vital for bone health, and vitamin D assists in bone metabolism and immune function, but their roles do not specifically target the prevention of neural tube defects.