AAPLOG statement on induced abortion and the subsequent risk of breast cancer (1).

There is very strong evidence in the world's scientific medical literature that induced abortion constitutes a significant risk factor for future breast cancer. Is it a real risk that every woman considering elective abortion should be appraised of? Or is it simply an unproven threat thrown into the abortion arena to frighten pregnant women from making "the choice"? These are absolutely vital questions for any abortion inclined pregnant woman. The threat of breast cancer, surgery, radiation, chemotherapy, disfigurement, even death, hang on the correct answers. We depend on "evidence based medicine" to guide us to valid conclusions on such issues. Here is the evidence:

There are two pregnancy related independent risk factors for breast cancer established in the medical literature. The first is the protective effect of an early first full term pregnancy. The landmark study establishing this protective effect by MacMahon et al. is widely accepted in the medical world. (2) MacMahon, and group reanalyzed their 1970 data finding that each one year delay in the first full term pregnancy increased relative breast cancer risk by 3.5% (compounded). Obviously, aborting a first pregnancy eliminates the protective effect against breast cancer. (3)

The second independent risk factor for breast cancer is induced abortion. As of March, 2002, there have been published in the world-wide medical literature thirty-seven studies reporting data on the risk of breast cancer among women with a history of induced abortion. Twenty-eight of these studies report increased risk. In the United States, there have been fifteen such studies, thirteen of which reported increased risk, eight with statistical significance (at least 95% probability that the result is not due to chance) irrespective of age at first full-term pregnancy The relative risk increase of the thirty-seven studies combined is thirty percent. (4)

Consider the implications of the study specifically funded by the United States National Cancer Institute to investigate the abortion/breast cancer link. (5) Janet Daling's group found an overall fifty percent breast cancer risk by age forty-five for women who have had an induced abortion. American women today have an approximately 12% lifetime chance of developing breast cancer. But the risk increases even more than fifty percent for certain subgroups. For example, among women with a family history of breast cancer (mother, grandmother, sister, or aunt), the...