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In Indiana, a measure has been introduced in the House that would require medical doctors to tell women seeking abortion that having the procedure comes with risks including “the possibility of increased risk of breast cancer following an induced abortion and the natural protective effect of a completed pregnancy in avoiding breast cancer.” Indiana isn’t the only state that makes this claim either. According to the Guttmacher Institute, five states — Alaska, Mississippi, Oklahoma, Texas and West Virginia — currently include some mention of a link between abortion and breast cancer in written counseling materials.
The connection between breast cancer and abortion that these state governments and other abortion opponents refer to comes from outdated data that has since been proven to be faulty. Since 1981, several dozen studies looking at a potential link between abortions and a woman’s risk of developing breast cancer have been published. Many of the older studies alleging a link between breast cancer and abortion were flawed; some studies included only a small sample size and most of the older studies were dependent upon self-reporting abortion data which is a scientifically unreliable method.
The American Cancer Society (ACS) and other major health organizations have soundly rejected any potential link between breast cancer and abortions. Over eight years ago, the U.S. National Cancer Institute brought together “more than 100 of the world’s leading experts who study pregnancy and breast cancer risk.” They found that neither induced nor spontaneous abortions lead to an increase in breast cancer risk. In fact, the risk is actually increased for a short period after a woman carries a pregnancy to full term. According to ACS, these findings were considered “well established,” which is the highest level for scientific evidence.
Even recently, in June 2009, the American College of Obstetricians and Gynecologists Committee on Gynecologic Practice wrote, “Early studies of the relationship between prior induced abortion and breast cancer risk were methodologically flawed. More rigorous recent studies demonstrate no causal relationship between induced abortion and a subsequent increase in breast cancer risk.”
The largest, and probably the most reliable study on this topic, was conducted during the 1990s in Denmark, a country with very detailed medical records on all its citizens. In this study, all Danish women born between 1935 and 1978 (a total of 1.5 million women) were linked with the National Registry of Induced Abortions and with the Danish Cancer Registry. All of the information about their abortions and their breast cancer came from registries – it was very complete and was not influenced by recall bias. After adjusting for known breast cancer risk factors, the researchers found that induced abortion(s) had no overall effect on the risk of breast cancer. The size of this study and the manner in which it was done provides good evidence that induced abortion does not affect a woman’s risk of developing breast cancer.
Another prospective study was published by Harvard researchers in 2007. The study included more than 100,000 women between the ages of 20 and 46 at the beginning of the study in 1993. These women were followed until 2003. They were asked about childbirths and abortions at the start of the study so recall bias was unlikely to be a problem. After adjusting for known breast cancer risk factors, the researchers found no link between either spontaneous or induced abortions and breast cancer.
The California Teachers Study also reported on more than 100,000 women in 2008. Researchers asked the women in 1995 about past induced and spontaneous abortions. While the women were being followed in the study, more than 3,300 developed invasive breast cancer. There was no difference in breast cancer risk between the group who had either spontaneous or induced abortions and those who had not had an abortion.
The research is clear that there is no link between abortions and breast cancer. However, many abortion foes continue to purport the myth, suggesting that pregnancy somehow protects women against breast cancer. It is a dangerous myth that even the governments are now spreading along for their own purposes. Women need to have the facts about breast cancer so that they can take the necessary steps to try to prevent it. Scaring women into believing a lie does nothing to prevent breast cancer.