Which of the following can lead to neural tube defects during pregnancy?

Folate deficiency is known to significantly increase the risk of neural tube defects during pregnancy. Folate, or vitamin B9, is essential for DNA synthesis, repair, and methylation, which are crucial processes in cell division and growth. During early pregnancy, especially in the first few weeks, adequate folate is necessary for the proper development of the neural tube, which eventually forms the brain and spinal cord. Without sufficient folate, the neural tube may not close properly, leading to defects such as spina bifida or anencephaly.

Public health initiatives often recommend that women of childbearing age take folic acid supplements and consume foods rich in folate to mitigate this risk, highlighting the recognized connection between folate levels and neural tube defect prevention. Other nutrients, while important, do not have the same established link to neural tube defects as folate does.