The occurrence of breast cancer is lower among women who have had infertility problems because of an ovulation disorder than among women who have not had difficulty conceiving. Researchers from the Harvard School of Public Health, Boston, evaluated data from more than 116,000 female nurses aged 25 to 42 years at baseline. Information on infertility and ovulation was assessed every 2 years starting in 1989, and cases of breast cancer were included through 2001. During follow-up, 1357 cases of invasive breast cancer were diagnosed. Overall, it was found that women who had ovulatory disorders had a 25 percent lower likelihood of developing breast cancer than those who did not. Moreover, the risk of breast cancer was lowest in women who underwent induced ovulation for treatment of infertility. The findings are reassuring since many women and their clinicians are concerned about the long-term implications of infertility treatment. However, it is difficult to tease apart the true effect of infertility drugs and infertility, since women who have the most difficultly getting pregnant will most likely be taking infertility drugs the longest.
Archives of Internal Medicine,
December 2006