Spina bifida occurs when the lower end of the neural tube fails to close properly, leaving the spinal cord exposed to the amniotic fluid. Eighty to ninety percent of infants born with spina bifida live with complications.

More about spina bifida:

Dr. Victor Klein, an OB/GYN with special training in high-risk pregnancies at New York's North Shore University Hospital, discusses spina bifida and what can be done to prevent it.

Dr. Godfrey Oakley, Jr., visiting professor of epidemiology at the Rollins School of Public Health at Emory University, discusses the CDC's efforts to alert women of childbearing age to the necessity of getting enough folic acid.