A myelomeningocele is a type of birth defect called a neural tube defect. It occurs when the bones of the spine (vertebrae) don't form properly around part of the baby's spinal cord. Spina Bifida can be mild or severe. Normally, the neural tube forms early in the pregnancy and closes by the 28th day after conception.
In babies with spina bifida, a portion of the neural tube fails to develop or close properly, causing defects in the spinal cord and in the bones of the spine. The mild form is the most common. It usually doesn't cause problems or need treatment. A rare and more severe form is meningocele. In this case fluid leaks out of the spine and pushes against the skin. You may see a bulge in the skin. In many cases, there are no other symptoms. The treatment for spina bifida is necessary, it's done surgically, although such treatment doesn't always completely resolve the problem.