Neural tube defects

What it is

Neural tube defects result from failure of normal fusion of the neural plate to form the neural tube during the first 28 days following conception. They are grouped by site. In the brain they are anencephaly and encephalocele. In the spine they are spina bifida occulta, meningocele and myelomeningocele. Spina bifida itself is a congenital abnormality with incomplete closure of the vertebral canal, because the vertebral arches fail to fuse, so the contents of the spinal canal herniate out. The most common site is the lumbosacral spine, and it can associate with hydrocephalus.

Causes and risk

The cause is Multi-factorial, but the most preventable one is folic acid deficiency, which can also cause anencephaly. The other listed causes are diabetes, sacral dysgenesis and sodium valproate. Maternal diabetes shows this: neural tube defects, named there as spina bifida and anencephaly, head the list of congenital anomalies of GDM, along with cardiac defects and caudal regression syndrome, which is very specific for maternal diabetes. Prevention is by folic acid. One recommendation is 0.4 to 0.8 mg daily for all women who are planning on or are capable of becoming pregnant. Another is 400 ug for those with no risk, and a folic acid supplement of 5 mg per day during pregnancy together with 3 months before conception.