Women who take multivitamins early in pregnancy may reduce the risk that their child will develop some types of brain tumors.

Public health agencies already urge pregnant women to take multivitamins that contain folic acid early in pregnancy to reduce their fetus's risk of developing neural tube defects, such as spina bifida. "This current study suggests another possible protective effect for the vitamins," said study leader Greta R. Bunin, Ph.D., of The Children's Hospital of Philadelphia. She added, "Children whose mothers took multivitamins close to the time of conception seemed less likely to suffer medulloblastoma and primitive neuroectodermal tumors of the brain."

While childhood brain tumors are relatively rare, medulloblastoma is the second most common brain tumor in children. Occurring in one in 20,000 children under age six, it appears in the cerebellum, the lower portion of the brain, and the area of the brain that coordinates movement. Primitive neuroectodermal tumors are similar to medulloblastoma but occur in other parts of the central nervous system.

Dr. Bunin led a study comparing 315 children diagnosed with those tumors before age six to 315 randomly chosen healthy children. The results appears in the September issue of Cancer Epidemiology Biomarkers and Prevention.

The researchers found that taking multivitamins later in pregnancy did not significantly reduce the child's risk of developing a brain tumor. "Our findings suggest that the time close to conception may be a critical period in the development of these tumors," said Dr. Bunin. "However, most women do not yet know they are pregnant at this very early stage. That is why women of reproductive age are advised to take multivitamins to prevent neural tube defects even if they are not trying to get pregnant."

"Taking multivitamins in the first few weeks of pregnancy definitely helps prevent neural tube defects," concluded Dr. Bunin. "While more research remains to be done, our findings suggest that multivitamins may prevent some brain tumors as well."