FRIDAY, July 6 (HealthDay News) -- Whether or not a woman becomes pregnant while on fertility drugs may affect her odds for breast cancer later on, a new study suggests.
However, experts who reviewed the study said it has flaws and is far from conclusive.
In the study, published July 6 in the Journal of the National Cancer Institute, women using ovulation-stimulating fertility drugs who were unable to get pregnant for at least 10 weeks had a lower risk of the disease than women who have not taken the drugs, the U.S. study found.
On the other hand, the odds of breast cancer rose for women who became pregnant for at least 10 weeks after taking the fertility drugs, when compared to women who were unsuccessfully treated with these drugs.
However, the risk for women who became pregnant while on fertility drugs rose only high enough to put it on par with women who had never taken fertility drugs, the researchers noted.
The researchers, led by Chunyuan Fei, at the U.S. National Institute of Environmental Health Sciences, examined women diagnosed with breast cancer before the age of 50, as well as their sisters who did not have the disease, over the course of two years.
"Our data suggest that exposure to a stimulated pregnancy is enough to undo the reduction in [breast cancer] risk associated with a history of exposure to ovulation-stimulating drugs," the authors wrote.
The study's authors pointed out that the study was limited by its reliance on the participants' self-reported fertility drug usage, and a lack of information on each woman's specific diagnosis for infertility. The study is also complicated by the fact that it focuses on women who developed breast cancer before the age of 50, and these tumors are often associated with genetic factors.
In an accompanying editorial, Louise Brinton, of the division of cancer epidemiology and genetics at the U.S. National Cancer Institute, noted th
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