It cannot be said that all women who have breast cancer have had abortions.  Similarly, not all women who have had abortions will get breast cancer.  Nevertheless, abortion is the most preventable risk factor for breast cancer.

There has been much debate over the link between abortion and breast cancer. As of September, 2002, twenty-nine out of the thirty-eight studies in the worldwide literature indicate an increased risk of breast cancer associated with induced abortion. Seventeen of the studies are “statistically significant,” a technical term which means the data provided at least 95% certainty that the association measured was not due to chance.

1. Approximately 1 in 100 women procuring an abortion is expected to die as a result of abortion-induced breast cancer.
    

2. The first study on a link between abortion and breast cancer was published in an English publication in 1957 and focused on Japanese women.  It showed a 160% increased risk of breast cancer among women who'd had an induced abortion.  [Segi et al. (1957) GANN 48 Suppl.):1-63]
    

3. Jane Orient, MD, a spokeswoman for the American Association of Physicians and Surgeons, told World Net Daily that, “If you look at the number of studies that show a connection, they vastly outnumber the ones that don’t, and the ones that don’t have been criticized for serious methodological flaws.” [John Dougherty, “Can doctors be sued over abortion? Those who don’t inform patients of breast cancer link could be targets,” World Net Daily, <www.worldnetdaily.com>, March 27, 2002]
    

Dr. Janet Daling, an abortion supporter, and her colleagues at the Fred Hutchinson Cancer Research Center were commissioned by the National Cancer Institute to conduct a study to determine if induced abortion raises breast cancer risk.  The study found that, "among women who had been pregnant at least once, the risk of breast cancer in those who had experienced an induced abortion was 50% higher than among other women."

High Risk Groups

Daling identified 3 high risk groups and reported these findings:
1) Women under the age of 18 or over the age of 29 who obtained induced abortions have more than a twofold increase in risk.

2) Women with a family history of breast cancer who procured an abortion were found to have statistically significant risk increases of 80 percent.

3) Teenagers with a family history of the disease who procured abortions before the age of 18 were found to have incalculably high risk.  All 12 women in Daling's study with this background were diagnosed with breast cancer by the age of 45.  [Daling et al. (1994) J Natl Cancer Inst 86:505-14.]

An additional high risk group was identified by Dr. Amelia Laing of Howard University:
 

African American women had a 50% increased risk before the age of 40, a 180% increased risk between the ages 41 and 49 and a 370% increased risk after age 50 if they'd ever procured at least one abortion. [Laing et al. (1993) J Natl Med Assoc 85:931-9] 

It is clear from these studies that there is a significant link between abortions and breast cancer. But why? For more information on the biology of this link, visit http://web.archive.org/web/20060926013737/http://www.abortionbreastcancer.com/. This site also contains many of the above studies in their entirety.