Spina bifida is a birth defect that occurs as a result of abnormal formation of a baby's backbone (spine), causing the nerves that branch out of it to be damaged. The bones (vertebrae) and/or skin surrounding the spine may be malformed, leading to serious infections, problems with bladder and bowel function, and, in serious cases, paralysis.
The medical condition occurs because of problems with the neural tube, which is an early form of the spinal cord in an embryo and usually forms early in the pregnancy and closes by the twenty-eighth day after conception. In some embryos, the neural tube may not form properly or may not close completely resulting in defects in the spinal cord and bones and tissues of the spine. Most cases of spina bifida occur in the lower back.
Children with spina bifida have a gap between their backbone and spinal canal. In some cases, the defect manifests as a visible opening in the back, through which a portion of the spinal cord and the meninges, the membrane that covers the brain and spinal cord spinal cord may push through (spina bifida aperta). These may be visible as a sac along the spinal canal, covered with a thin layer of skin.
In other cases, the defect may not be visible and remains hidden under the skin (spina bifida occulta). Many people with this mild form of spina bifida may not even know they have this disorder as it doesn't cause any neurological symptoms.
Low levels of the vitamin folic acid during pregnancy are believed to be a cause of spina bifida. However, it may also occur in mothers who took pre-natal vitamins, though the cause of this is not known. It is also believed that viral infection, certain medications, and environmental conditions, such as radiation, also may also contribute to this disorder.