Spina bifida is a condition in which the spine fails to develop properly. There is a range of possible results, from a small hole in the backbone that is hidden under the skin and causes no symptoms, to a large gap in the bones and skin, leaving the nerve tissue of the spinal cord exposed outside the body. Spina bifida is one of a group of conditions known as neural tube defects. A connection between folic acid and spina bifida exists because taking folic acid during pregnancy has been shown to help prevent neural tube defects from occurring.
In the US, a policy of adding folic acid, also called vitamin B9, to foods has reduced the number of cases of neural tube defects, such as spina bifida, by around one fifth. Studies into the relationship between folic acid and spina bifida have shown that up to 70 percent of cases of spina bifida could be prevented by taking enough folic acid both before and during the early stages of pregnancy. Spina bifida is more likely to occur in babies of women who have the condition themselves or who have had a previous pregnancy resulting in a child with either spina bifida or another neural tube defect.
The critical phase of pregnancy during which spina bifida may develop is thought to lie between day 17 and day 30. In many cases, a woman may not be aware that she is pregnant at such an early stage. For this reason, some authorities recommend that all women should take folic acid supplements when they are planning to become pregnant. Research into folic acid and spina bifida has revealed that spina bifida may not always arise solely from a folic acid deficiency in the mother. It is thought that some people with spina bifida may have a genetic problem that means they are unable to make use of folic acid in the normal way.
Even though knowledge concerning the connection between folic acid and spina bifida has led to a fall in the number of babies being born with the condition, around one baby in every 1,000 has spina bifida. Surgery may be needed to treat problems with leg paralysis, bladder and bowel function, and excess fluid in the brain. Advances in surgery have meant that it is possible to correct some defects while the baby is in the womb. The outlook for most people with spina bifida is that they will survive to become adults and have a reasonable quality of life.