Spina bifida is one of the most common birth defects.  It affects about 1 out of 1000 babies born each year.  Spina bifida is caused by the failure of the spine to close properly during the first month of pregnancy.

There are three types of Spina bifida:
 

About 40% of the Americian population have Spina Bifida Occulta, but becasue of the lack of major symptoms, they don't know it.  meningocele and myelomeningocele combined make up about one out of 1000 births.  Of that one birth meningocele occurs in about 4% of the births and myelomeningocele occurs in 96% of the births.

There is no known cure for spina bifida.  There is some thought to the birth defect being genetical in nature.  There is also some belief that folic acid, found in foods such as green vegetables and orange juice help prevent neural tube defects such as spina bifida.