NEW YORK (Reuters Health) - The risk of developing cancer later in life is decreased among women whose pregnancies were affected by preeclampsia, according to the results of a study published in the American Journal of Obstetrics and Gynecology.

Dr. Kjersti M. Aagaard-Tillery and colleagues from the University of Utah, Salt Lake City, performed a study in which preeclamptic women were identified between 1947 and 1999 from the Utah Population Database. Overall, 17,432 women with preeclampsia were matched to 52,296 non-preeclamptic women for maternal age and birth year.

Preeclampsia is a condition of pregnancy that usually begins with high blood pressure. The disorder may also lead to seizures, kidney failure or stroke. It slows the growth of the fetus, can cause early delivery, and can be fatal for the mother and the infant. The cause is unknown and there is no treatment, except to manage the symptoms.

Overall, 2617 (5.25 percent) of the non-preeclamptic women subsequently developed cancer, compared with 760 (4.79 percent) of the preeclamptic women.

Preeclampsia was associated with a 9-percent lower risk of cancer, Dr. Aagaard-Tillery and colleagues report. After accounting for the possible influence of other factors, the preeclamptic women still had an 8 percent lower risk when compared with the non-preeclamptic women.

The investigators report the results "have both epidemiologic and biologic merit," noting that others have reported a protective effect of preeclampsia on breast cancer.

However, the researchers think it unlikely that preeclampsia itself is the protective factor. They hypothesize that a subgroup of women who develop preeclampsia are genetically predisposed to have an increased risk of developing atherosclerosis and blood clots and a decreased risk of cancer.

SOURCE: American Journal of Obstetrics and Gynecology, September 2006.