What causes neural tube defects?
The most common causes of neural tube defects are insufficient folic acid in the mother's diet, both before she became pregnant and during the first few weeks of pregnancy. Several other factors may contribute to the development of neural tube defects as well, including poor nutrition, certain drugs, and exposure to chemicals or radiation. In a few families,
there also appears to be a genetic predisposition.
All pregnancies are at risk for an neural tube defect. However, women with a history of a previous pregnancy resulting in a fetus with an neural tube defect are at higher risk. So are women with a close relative (brother, sister, niece, or nephew) who has an neural tube defect, women with type 1 diabetes mellitus, women with seizure disorders being treated with valproic acid or carbamazepine, and women or their partners who themselves have an neural tube defect.
When neural tube defects occur concurrently with other malformations, there is a greater likelihood of an underlying specific genetic or environmental cause. Genetic causes include chromosome aberrations and single gene mutations. Environmental causes include maternal diabetes mellitus, exposure to prolonged hyperthermia, and taking seizure medications during the early months of pregnancy.