Spina bifida means split spine. Fetuses with spina bifida, one of the most common birth defects, develop with the two sides of the neural tube, a sheath of tissue that will form the spine, incompletely joined. This leads to gaps in the protective covering the spine normally provides for the spinal cord. When this happens, the baby’s nervous system is highly prone to infections that the neural tube ordinarily protects against. These infections can result in lifelong nervous system damage. In addition, the damaged neural tube causes cerebrospinal fluid to build up in the skull, putting pressure on the brain.
Infants with spina bifida may have paralysis of the legs, bowel and urinary incontinence, cognitive difficulties, or learning disabilities. The cerebreospinal fluid can cause or exacerbate these difficulties. In some cases, different parts of the neural tube, which will become parts of the brain itself, fail to join, leading to brain damage when the baby is born.
It is unclear exactly what causes spina bifida. There is a genetic component, but environmental factors are also known to be partly responsible. In particular, folic acid levels seem to be related to proper fusion of the neural tube, to the point that, though only about a third of pregnant women take folic acid, women who do so are 70 percent less likely to have babies with spina bifida. However, neural tube fusion is supposed to happen less than a month into pregnancy, before the expectant mother even necessarily realizes she’s pregnant. For this reason, some experts recommend that all women who intend or expect to become pregnant should take folic acid.
Another possibility is surgery on the fetus in the uterus. If ultrasound or other imaging shows incomplete neural tube fusion, surgical techniques are being investigate that will allow a surgeon to go in and fix the damage before the birth. In one study, this was shown to be cost-effective, sparing parents the financial costs of repeated surgeries and other treatments after birth. Prenatal in utero surgery also means the damage that the condition starts doing immediately after birth can be reduced, if not entirely eliminated. Research has shown that prenatal surgery prevents the buildup of cerebrospinal fluid, and babies born after surgery are more likely to eventually be able to walk unaided.