A new study suggests birth control pills may increased the already heightened risk of breast cancer faced by women with a family history of the disease. Researchers report in the Journal of the American Medical Association:

• Among sisters and daughters of women with breast cancer, pill users were three times more likely than non-users to get the disease.

• If at least five family members had breast or ovarian cancer, women who used the pill had an 11 times greater risk of developing the disease themselves.

Researchers noted that the risks were linked to forms of the pill made before 1975 which had higher hormone levels. But an accompanying editorial said it was unclear whether the risk was linked only the older pills, noting granddaughters in the study, whose average age was 43, may just be too young for breast cancer to have developed.

However, birth control pills are one of the few proven methods for reducing the risk of ovarian cancer, which is harder to detect and often more deadly than breast cancer.

Source: Dawn M. Grabrick, et al., "Risk of Breast Cancer With Oral Contraceptive Use in Women With a Family History of Breast Cancer," Journal of the American Medical Association, October 11, 2000; Associated Press, "Pill May Raise At-risk Women's Breast Cancer Rate," Dallas Morning News, October 11, 2000.