Which of the following supplements is important for preventing neural tube defects during pregnancy?

Folic acid is crucial for preventing neural tube defects during pregnancy due to its role in DNA synthesis and cell division. Neural tube defects, such as spina bifida and anencephaly, result from improper closure of the neural tube during the early stages of fetal development, which typically occurs within the first month of pregnancy. Adequate folic acid intake before conception and during early pregnancy significantly reduces the risk of these defects.

Health authorities recommend that women who are planning to become pregnant or who are in the early stages of pregnancy take a daily supplement containing folic acid, typically advised at doses of 400 to 800 micrograms. This is because the neural tube forms early in gestation, often before many women even know they are pregnant. Therefore, establishing sufficient folic acid levels is essential for optimal fetal development and lowering the risk of neural tube defects.