Abortion does not increase the risk of breast cancer, according to a study published in the October 2006 issue of the International Journal of Cancer.1 The researchers reported no association between one or more induced abortions and breast cancer risk. Women who had one miscarriage (spontaneous abortion) did not have an increased risk of breast cancer, and women who had two or more miscarriages had only a slightly increased risk of the disease (relative risk 1.20). The study examined induced abortion and miscarriage separately because of potential differences in hormonal changes between the two ways that a pregnancy might end without a live birth.
The study was part of the European Prospective Investigation in Cancer and Nutrition (EPIC) study, a multicenter prospective study designed to investigate the relationship between nutrition, lifestyle, and environmental factors and cancer. For the abortion and breast cancer study, researchers followed 267,361 women enrolled in the EPIC study for an average of 6.6 years, collecting information about all miscarriages or induced abortions and invasive breast cancer diagnoses. Data came from 20 centers across nine countries. Breast cancer was diagnosed in 4,805 women during follow-up, and 1,657 reported having had an induced abortion or miscarriage.
The findings of this study provide further evidence that abortion does not increase breast cancer risk. For information about past studies looking at abortion and breast cancer risk, see “Abortion and Breast Cancer: A Moral Position as a Conflict of Interest” in BCA Newsletter # 71.
1 Gillian K. Reeves, et al., “Breast Cancer Risk in Relation to Abortion: Results From the EPIC Study,” International Journal of Cancer 119(7), October 2006, pp. 1741-1745.