What are neural tube defects?
Neural tube defects are a group of malformations that occur when the brain, skull, spinal cord, and/or spine do not form normally. The age of the mother does not affect the risk of having a child with a neural tube defect.
The most severe type of defect is called anencephaly in which the brain and skull do not develop. Babies born with this condition die shortly after birth. The other major type of neural tube defect is spina bifida. In this disorder, the spinal column and/or spinal cord does not form properly. The severity of this disorder varies depending on the part of the spine involved and the amount of injury to the spinal cord and nerves.
A child may develop normally, have a moderate degree of handicap, or be severely handicapped. Common problems found in association with spina bifida include: hydrocephalus (extra fluid in the brain), mental retardation, inability to control bowel or bladder function, and paralysis or weakness of the legs. Some individuals with spina bifida can walk, while others are confined to a wheelchair.
Overall, approximately two infants per every thousand births are affected by a neural tube defect. Taking folic acid prior to pregnancy can reduce the risk of neural tube defects and other malformations. A small number of families are at increased risk of having a child with a neural tube defect because someone in their family had this disorder. Some medications (especially seizure medications) as well as diabetes can increase the risk of neural tube defects. However, 95% of women who have a fetus with a neural tube defect have no family history or risk factors! These women can only be identified by a screening test.