Children born to women who have low blood levels of vitamin B12 shortly before and after conception may have an increased risk of a neural tube defect, a new study says.

Women with the lowest B12 levels had five times the risk of having a child with a neural tube defect compared to women with the highest B12 levels. Women who consume little or no meat or animal based foods were the most likely to have low B12 levels, according to the joint study by the U.S. National Institutes of Health (NIH), Trinity College Dublin, and the Health Research Board of Ireland.

"Vitamin B12 is essential for the functioning of the nervous system and for the production of red blood cells," said Duane Alexander, director of the National Institute of Child Health and Human Development (NICHD).

Researchers have known that taking another nutrient, folic acid, during the weeks before and after conception can greatly reduce a woman's chances of having a child with a neural tube defect. Folic acid, which is the synthetic form of vitamin B. Neural tube defects, is a class of birth defects affecting the brain and spinal cord.

In the United States, cereal grains are fortified with folic acid to reduce the occurrence of neural tube defects in the U.S. population.

Ireland has a high rate of neural tube defects, and NIH scientists have frequently collaborated with Irish researchers to gain insight into the causes of this group of disorders.

"The results of this study suggest that women with low levels of B12 not only may risk health problems of their own, but also may increase the chance that their children may be born with a serious birth defect." Alexander said.

The study appears in the March issue of the U.S. journal of Pediatrics.

(Xinhua News Agency March 4, 2009)