Folic acid prevents neural tube birth defects

Neural tube defects (NTDs) are a group of serious birth defects including spina bifida and anencephaly that occur before most women are even aware that they are pregnant. NTDs happen when the neural tube, which forms the brain and spine, fails to close properly around the fourth week of pregnancy. This can result in physical abnormalities that can vary from minor to fatal.

NTDs are common birth defects and occur in about 200 pregnancies each year in North Carolina.

While scientists don't completely understand how folic acid prevents NTDs there is ample evidence to suggest that it does. That’s why the standard recommendation is for women to take a multivitamin containing 400 micrograms of folic acid every day.

Spina bifida

Spina bifida is a condition that affects the spine and is usually apparent at birth.  Spina bifida can happen anywhere along the spine if the neural tube does not close all the way. The backbone that protects the spinal cord does not form and close as it should. This often results in damage to the spinal cord and nerves.

Spina bifida might cause physical and mental disabilities that range from mild to severe.  The severity depends on:

  • The size and location of the opening in the spine. 
  • Whether part of the spinal cord and nerves are affected.

Some of the disabilities caused by spina bifida are leg paralysis, bladder and bowel problems, and/or other serious health complications. In most cases, the larger the defect is or the higher it occurs on the spine, the greater the disability. Children born with this condition usually require surgery in the first few days of life. Most people with spina bifida need to use a wheelchair or leg braces throughout their life.

Some people with spina bifida have little or no noticeable disability. Others are limited in the way they can move or function. They even might be paralyzed (unable to walk or move parts of the body). Even so, with the right care, most people affected by spina bifida will be able to grow up to lead full and productive lives.


Anencephaly (an-en-sef-uh-lee) is a serious birth defect in which a baby is born without parts of the brain and skull. This defect happen during the first month of pregnancy, usually before a woman knows she is pregnant. As the neural tube forms and closes, it helps form the baby’s brain and skull (upper part of the neural tube), spinal cord, and back bones (lower part of the neural tube).

Anencephaly happens if the upper part of the neural tube does not close all the way. This often results in a baby being born without the front part of the brain (forebrain) and the thinking and coordinating part of the brain (cerebrum). The remaining parts of the brain are often not covered by bone or skin.

Unfortunately, almost all babies born with anencephaly will die shortly after birth. CDC estimates that each year, about 1 in every 4,859 babies in the United States will be born with anencephaly.

Other birth defects

Folic acid might help to prevent some other birth defects, such as cleft lip and palate and some studies show that it might also protect against some heart defects. There might also be other health benefits of taking folic acid for both women and men. More research is needed to confirm these other health benefits. All adults should take 400 micrograms (mcg) of folic acid every day.

Content and images provided by Division of Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention. The original content can be found at and 

Revised: October 1, 2012

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