A neural tube defect (NTD) is a birth defect that occurs when the
spine, the brain, or the bone and skin that protect them do not develop
properly. The most common type of neural tube defect is spina bifida, in which
the spinal cord or spinal nerves may bulge out through an opening in the bones
of the spine.
The neural tube is the part of a developing fetus that grows into
the spinal cord and brain. Normally, the bones of the skull and spine grow
around the brain and spinal cord, and then skin covers the bones, creating the
neural tube. A neural tube defect occurs when this process doesn't happen
Neural tube defects can be found with prenatal tests, such as
ultrasound and amniocentesis. In spina bifida, treatment depends on the
severity. Surgery may be done to repair the spinal defect or to correct
complications. Physical therapy, braces, and other treatments may be necessary
to help the child with problems resulting from nerve damage.
Anencephaly is the second most common type of neural tube defect.
In anencephaly, the infant is born with only a partially formed brain and
spinal cord. This condition is always fatal.
Neural tube defects may be prevented if a woman takes folic acid
before becoming pregnant and during the first 6 weeks of pregnancy. But often a
woman does not know she is pregnant until after the first 6 weeks of pregnancy.