The Research

There are 39 studies worldwide that link abortion to an increased risk of breast cancer. Thirty-three report risk elevations, 17 of these studies are statistically significant, 16 of which demonstrate a positive association. These studies have explored abortion as an independent link to breast cancer. The independent link is found by comparing women with abortions to women who have not been pregnant. Compared to women who have not had a pregnancy, an abortion is an exposure that increases risk beyond the risk level attributable to the non-pregnant state.

Fifteen studies have been conducted on American women, of which 13 report risk elevations. Seven found a more than a twofold elevation in risk. (The term "statistically significant" means that scientists are at least 95% certain that their findings are not due to chance or error.)

The Brind Meta-Analysis

Commenting on the 2001 report, Dr. Joel Brind, PhD, Professor of Biology, Chemistry, and Endocrinology at Baruch College in New York stated "abortion can explain the entire rise in breast cancer since the mid 1980’s and it’s not just because the rise is in women young enough to have had an abortion. It is also that the absolute numbers of increased cases fall within the range of numbers that we predicted in our 1996 meta-analysis."

Dr. Brind is the lead author of the 1996 Review and Meta-analysis that looked at the entire body of abortion breast cancer research and found an overall 30% increased risk among women having an abortion and a 50% increased risk among women aborting before a first full term pregnancy.

Research History

The history of research into the ABC link goes back a long way. The first epidemiological study was done in Japan and found a 160% elevation in risk among women who had obtained abortions. It was reported in an English language journal in 1957. A second Japanese study was done in 1968 that found a relative increased risk of 1.51 or 50% for breast cancer in women who had had abortions.

The first study to examine the abortion-breast cancer link among American women was published in 1981 and reported that abortion "appears to cause a substantial increase in risk of subsequent breast cancer." A 2.4-fold increase or 140% risk elevation was reported.

The Howe1989 study found a statistically significant association in American women. The Howe study specifically used medical records of abortion, not interviews after the fact. The study reported a 90% increased risk of breast cancer among women in New York who had chosen abortion. They also found that a "first trimester abortion before a first full term pregnancy, whether spontaneous or induced, was associated with a 2.4 – fold increase in breast cancer risk."

Janet Daling et al. 1994

The findings of one of the largest studies (1800 women) conducted by Dr. Janet Daling and her colleagues at Seattle’s Fred Hutchinson Cancer Research Center in 1994 were especially disturbing. Dr. Daling, an abortion supporter, 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."

Daling’s team also found that teenagers under age 18 and women over 29 years of age who procure an abortion increase their breast cancer risk by more than 100%. Those with a family history of the disease increase their risk 80%. Daling’s most alarming finding was that teenagers with a family history of breast cancer who procure an abortion face a risk of breast cancer that is incalculably high. All 12 women in her study with this history were diagnosed with breast cancer by the age of 45.

Daling’s findings are not unique. The first of the US studies was done by Pike and colleagues and was initially funded by the US National Cancer Institute. It was published in the British Journal of Cancer and uncovered a 137% increased risk of breast cancer. Pike and colleagues concluded that "a first trimester abortion…before first full-term pregnancy appears to cause a substantial increase in risk of subsequent breast cancer. Our finding makes biological sense if one considers breast tissue as merely proliferating in early pregnancy; the protective effect of a first full-term pregnancy is then brought about by a combination of cell differentiation and possibly permanently altered hormone levels."