April 17, 2003 -- Taking folic acid supplements before and during early pregnancy may not only help prevent neural tube defects in babies, but it may also reduce the risk of Down syndrome. A new study suggests there might be a link between the Down syndrome and neural tube defects, and folic acid supplements may be an effective way to prevent both.
Neural tube defects are caused by the abnormal development of the brain and spinal cord during early pregnancy. The most severe neural tube defects can cause devastating mental and physical impairment. Numerous studies have shown that taking folic acid supplements before and during pregnancy can significantly reduce the risk of neural tube defects.
Down syndrome is one of the most common birth defects, and children born with the condition usually have some degree of mental retardation as well as distinctive physical features. Although the risks of developing Down syndrome are not well understood, the mother's age and family history are known to increase the risk.
Researchers say previous studies have shown that mothers of children with Down syndrome and neural tube defects tend to share problems in processing folic acid, which prompted them to see if both defects occurred more often in the same family than in others.
The study, which appears in the April 19 issue of The Lancet, compared the number of children born with either defect among pregnancies at risk for neural tube defects or Down syndrome due to a family history of the defects.
They found that more than five times the number of pregnancies (11) were affected by Down syndrome among the 1,492 pregnancies in Israeli families at risk for neural tube defects compared with other women of the same age. A similar increase in the number of neural tube defects were found among Ukrainian families at risk for Down syndrome, with seven times the expected incidence of the defect among the 1,847 pregnancies studied.
Researchers say this study provides the first proof that Down syndrome and neural tube defects may share some similarities in how they develop and who's at risk.
"Although the underlying mechanism for the connection between Down syndrome and NTD [neural tube defects] needs to be established, the direct evidence of a link between the disorders shown in this report raises the question of the reduction of risk of Down syndrome through folic acid supplementation," write researcher Gad Barkai, of Tel Aviv University, and colleagues.
In an editorial that accompanies the study, Jorgen H. Olsen and Jeanette Falck Winther, of the Institute of Cancer Epidemiology in Denmark, say that more research is needed before folic acid supplements can be recommended to prevent Down syndrome in the general population.
"Nevertheless, although the report is somewhat provocative, it may well be the first epidemiological indication of the existence of a mechanism which could be used at a later stage in the primary prevention of [Down syndrome]," they write.
SOURCE: The Lancet, April 19, 2003.