“Spina bifida is a type of neural tube defect that happens when a fetus’s spine and spinal cord don’t close properly during early pregnancy.

The neural tube forms the brain and spinal cord during embryonic development. When it doesn’t close, it leaves a gap in the spine. This gap can affect the vertebrae, spinal cord and nearby nerves. In more severe cases, a fluid-filled sac may stick out through the opening.

Symptoms range in severity.”

Cleveland Clinic (Spina Bifida: What It Is, Causes, Symptoms & Treatment)