David Limbaugh claimed a "statistical correlation between abortion and breast cancer"; National Cancer Institute disagrees
In his November 23 nationally syndicated column, David Limbaugh, brother of right-wing radio host Rush Limbaugh, reprimanded pro-choice advocates for not "inform[ing] women of the statistical correlation between abortion and breast cancer." But according to the National Cancer Institute and other medical researchers, there is no such statistical correlation between the two; abortions are "not associated with an increase in breast cancer risk."
Limbaugh wrote in his November 23 column :
If these [pro-choice] groups and their likeminded advocates and servants in government were for promoting choice, they would inform women of the statistical correlation between abortion and breast cancer and the likelihood that pregnant women who have abortions will suffer emotional or psychological damage as a result.
The National Cancer Institute  (NCI), a component of the National Institutes of Health, is the U.S. government's "principal agency for cancer research and training." According to a March 2003 NCI report  on abortion, miscarriage, and breast cancer risk, neither "[i]nduced abortion" nor "[r]ecognized spontaneous abortion" are "associated with an increase in breast cancer risk." The report was based on the findings of a February 2003 workshop on early reproductive events and breast cancer; the NCI's board of scientific advisers and board of scientific counselors reviewed and discussed the findings and declared them to be well-established.
An NCI "Cancer Facts" report  on the findings of the same breast cancer workshop addressed the questionable nature of studies that do show a link between abortion and breast cancer, stating:
Most of these studies, however, were flawed in a number of ways that can lead to unreliable results. Only a small number of women were included in many of these studies, and for most, the data were collected only after breast cancer had been diagnosed, and women's histories of miscarriage and abortion were based on their "self-report" rather than on their medical records. Since then, better-designed studies have been conducted. These newer studies examined large numbers of women, collected data before breast cancer was found, and gathered medical history information from medical records rather than simply from self-reports, thereby generating more reliable findings. The newer studies consistently showed no association between induced and spontaneous abortions and breast cancer risk.
The NCI report was corroborated by a March 2004 report  in the British medical journal The Lancet, which discussed the findings of an analysis of several international studies on the relationship between breast cancer and abortion. The analysis, which was conducted by the Collaborative Group on Hormonal Factors in Breast Cancer and used data from 53 studies conducted in 16 countries with "liberal" abortion laws, concluded: "Pregnancies that end as a spontaneous or induced abortion do not increase a woman's risk of developing breast cancer."