"Neural tube defects are a common type of birth defect that originate within the first four weeks after conception. In the affected fetus, the nervous system the brain and spinal chord does not form properly. Spina bifida and anencephaly are two well-known types of neural tube defects.
Infants with these birth defects experience a host of short and long-term health consequences, including paralysis, stillbirth and death. While taking folic acid before and during pregnancy can prevent the condition, the cause of these severe defects, in most cases, remains a mystery to doctors and scientists."