Spina Bifida

I’m pregnant and my obstetrician recommended that I take folic acid to guard against my baby developing spina bifida.  What is spina bifida?

   Spina bifida affects approximately 2,000 babies each year and is one of the most common severe birth defects in the United States.  A defect of the backbone and sometimes the spinal cord, it’s one of a group of birth defects called neural tube defects (NTDs).  The neural tube is the embryonic structure that develops into the brain and spinal cord.  NTDs occur when the vertebrae and/or spinal cord of the fetus fail to develop properly.  Varying degrees of damage to the spinal cord and nervous system may result.  Unfortunately, once damage occurs, it is permanent.

The effects of spina bifida
   Every unborn baby’s spine is open when it first forms but normally closes by the 29th day following conception.  In a baby with spina bifida, the backbone never closes completely.  There are three forms of this condition.

Occulta is the mildest form of spina bifida.  It results in a small separation of the spinal bones. The problem is a small defect or gap in one or more of the vertebrae.  Because the spinal nerves are not involved, most babies with this form have no signs or symptoms.

Meningocele is the rarest form of spina bifida.  In this type, a cyst or lump, consisting of membranes surrounding the spinal cord, pokes through the open part of the spine. The cyst can be surgically removed, however, allowing the baby to develop normally.

Myelomeningocele is the most severe form of spina bifida.  The baby's spinal canal remains open along several vertebrae in the lower or middle back. Because of this opening, both the membranes and the spinal cord protrude at birth, forming a sac on the baby's back. In some cases, skin covers the sac. But in most cases, tissues and nerves are exposed, making the baby prone to life-threatening infections.  In spite of surgery, nerve damage is permanent, and varying degrees of paralysis and bladder and bowel control problems remain for life.

Folic acid key to prevention
   Ninety-five percent of babies born with spina bifida and other NTDs are born to parents with no family history of these disorders.  Although the specific causes of spina bifida are still unknown, recent research indicates that the development of this condition may be influenced by the mother’s diet, especially the amount of the B vitamin folic acid she consumes.

   Because spina bifida and other NTDs occur during the first month of pregnancy, it is important for women to begin taking folic acid at least one month before conception and during the first month of pregnancy.  Since women usually don’t realize that they are pregnant for several weeks, women of childbearing age should take the recommended amount of folic acid (0.4 milligrams) daily.  It is difficult to consume this amount through diet alone, so the U.S. Public Health Service recommends that all women of childbearing age take a daily supplement or multivitamin containing 0.4 milligrams.  However, it is important to note that, unless prescribed by a physician, the U.S. Public Health Service cautions against exceeding one milligram of folic acid on a daily basis.

Dr. Narula is Chairman of Pediatrics, New York Methodist Hospital