Women are currently recommended to consume certain amounts of folic acid to reduce the risk of spina bifida and other birth defects, and in countries that have mandated folic acid fortification of flour, prevalence of neural-tube defects has been halved, with a similar benefit on incidence of the deadly childhood cancer neuroblastoma.
But most countries have not introduced such a policy and each year about 3 per cent of all new births around the world are affected with major structural birth defects, the biggest cause of infant mortality and disabilities among children in industrialized countries.
The new findings suggest that pregnant women should also increase their levels of vitamin B12 to prevent some of these birth defects.
Writing in the July issue of the American Journal of Obstetrics and Gynecology (vol 191, issue 1, pp11-17), scientists from the University Medical Center Nijmegen said they measured vitamin B12 levels in blood samples from 45 mothers and their children with spina bifida and from 83 mothers and their healthy children.
Mothers of children with spina bifida had vitamin B12 levels that were 21 percent lower than those of other mothers. With the lowest levels, the risk of spina bifida was increased more than threefold.