Neural tube defects occur very early in fetal development and cause very serious
birth defects. The area that is to form the brain and the spinal cord actually starts as a
hollow Neural Tube that develops just underneath what will become the skin of the back.
Neural tube formation is normally complete 4 weeks after fertilization. Failure of neural
tube fusion leads to permanent developmental defects of the brain and spinal cord or both.
These defects are called anencephaly, meningomyelocele (which is commonly called spina
bifida ), and encephalocele. Although there are many genetic factors, folic acid
deficiency is clearly related to neural tube closure defects. About 90% of open neural
tube defects can be detected by estimation of Alpha
Feto Proteins in the mothers blood.