Spina bifida is when a baby’s spine and spinal cord does not develop properly in the womb, causing a gap in the spine. Spina bifida is a type of neural tube defect. The neural tube is the structure that eventually develops into the baby’s brain and spinal cord. The neural tube starts to form in early pregnancy and closes about 4 weeks after conception. In spina bifida, part of the neural tube does not develop or close properly, leading to defects in the spinal cord and bones of the spine (verteb