Prenatal folate averts child leukemia. (Astronomy).

Because a deficiency of folic acid, or folate, can lead to birth defects, pregnant women are encouraged to consume foods rich in the substance or to take supplements. There's another reason for expectant mothers to pay attention to folate: Even a little extra appears to reduce the risk that the child will develop leukemia.

Judith R. Thompson of the Cancer Foundation of Western Australia in West Perth and her colleagues followed 83 children under the age of 15 who had acute lymphoblastic leukemia, and twice the number without the disease. The most common childhood cancer in industrialized countries, this cancer has been associated with parental exposure to toxic and infectious agents, genetic variations (SN: 11/6/99, p. 293), and several other factors.

The researchers questioned the children's parents about family members' personal and medical histories, including dozens of factors with known or suspected links to the leukemia. The team also recorded data about other factors, one of them folate use, without a suspected link.

To their surprise, the researchers found that one of the strongest statistical relationships with the disease's incidence was whether or not the child's mother had taken folate supplements during pregnancy. Supplements were effective regardless of when expectant mothers began taking them, or for how long, the researchers report in the Dec. 8, 2001 LANCET. --B.H.