A Neural Tube Defect (NTD) is a birth defect that occurs when the neural tube, which forms the baby's brain and spinal cord, does not close completely during early pregnancy. This can lead to serious conditions such as spina bifida or anencephaly, affecting the baby's development and overall health. NTDs can be influenced by various factors, including genetic predisposition and environmental influences. Taking folic acid supplements before and during pregnancy is known to reduce the risk of NTDs, making it an important preventive measure for expectant mothers.