Spina bifida is a serious birth defect in which an unnatural opening occurs between the bones of a baby’s spinal column. The defect may allow a sac of spinal tissue and nerves to protrude through the skin of the back. The defect can cause problems such as paralysis, motor difficulties and an enlarged skull.

Spina bifida is a type of neural tube defect. It occurs very early in pregnancy, when the tissue that forms the brain and spinal cord fails to develop properly. The interrupted development can affect nerves and muscles, mostly in the lower body. Changes in the fluid of the spinal cord may also affect the brain and cause fluid to build up there in a condition called hydrocephalus.

Many cases of spina bifida are caused by a deficiency of folic acid, a B vitamin. Folic acid contributes to the growth of cells, although the specifics of its role in spina bifida are not well understood. Some other risk factors for having a child with spina bifida include the use of some anticonvulsant medications and family history or ethnic origin.

Some forms of spina bifida are extremely mild, produce no symptoms and may never be identified (spina bifida occulta). However, most children born with spina bifida have a severe form where spinal membranes and nerves are outside the body and have been damaged. These cases of spina bifida are treated with surgery almost immediately after birth to reposition the spinal tissue back inside the body. However, damage to the nerves cannot be reversed and may cause paralysis, bowel and bladder problems, and some developmental disabilities. These forms of spina bifida require lifelong management with the involvement of many medical professionals.

Spina bifida is usually diagnosed during pregnancy. A blood test administered sometime in the 16^th to 18^th weeks of pregnancy shows higher levels of a certain protein for fetuses with spina bifida. Women who have a positive result on this blood test will undergo other tests (e.g., amniocentesis) to confirm the diagnosis. The prenatal diagnosis enables the physician to prepare for a Caesarean delivery and the possibility of immediate surgery after delivery. Research is under way to study the use of in-utero surgery to repair spina bifida defects.

Repair surgery, either before or after birth, can fix the injury but cannot repair the neurological damage caused by spina bifida. In addition to surgical repair on the back, most children with severe spina bifida require surgeries on other joints or bones.

Spina bifida is one of the most preventable birth defects. Studies have shown that maternal intake of folic acid before and early in pregnancy can reduce the incidence of neural tube defects such as spina bifida. Most medical associations in the United States recommend that all women of childbearing age should take 400 micrograms of folic acid per day, regardless of any plans for pregnancy. Folic acid is available in multivitamins, in green leafy vegetables and is added to many grain-based foods such as breakfast cereals.