For the LAST TIME, Abortion Does Not Cause Breast Cancer

The overwhelming scientific evidence does not support claims that abortion causes breast cancer, and members of the anti-choice movement are extremely reluctant to hear or admit this.
Publish date:
April 2, 2012
abortion, science, Breast Cancer, pro-choice

New Hampshire just voted on a doozy of an anti-choice bill that originally included a clause requiring doctors to lie to patients, telling them that abortion causes breast cancer. This isn’t the first state to include that kind of language in anti-choice legislation, and the “abortion causes breast cancer” myth is also repeated by a lot of anti-choice organizations. The problem isn’t limited to the US; in the United Kingdom, children are being given false information about abortion in school presentations.

This canard should have been well and truly put to rest by now, but of course the anti-choice movement is revving up this year, and it’s counting each little chip away at our rights as a victory. And as grounds to keep hammering. Hence, false statements about abortion and breast cancer are swirling around, and we’re having to waste a lot of energy explaining that there is no increased risk of breast cancer associated with abortion.

The false link has become a controversial topic, and it’s not helped by an imperfect understanding of science, compounded by several very flawed studies that originally suggested there was a correlation. The American Cancer Society has a good breakdown of the flaws with earlier studies, but in a nutshell, most included a sample size that was too small, and they were subject to what is known as “recall bias”:

Studies have also shown that healthy women are less likely to report that they have had induced abortions. In contrast, women with breast cancer are more likely to accurately report their reproductive histories. This may be because they are searching their memories for anything that may be linked to the cancer.

Because these studies focused on women who already had breast cancer, there were some serious methodological flaws. This was also made more complex because abortion was illegal in the United States until the 1970s, making many early study subjects reluctant to be honest about their medical history. Changing to what's known as a prospective study design, where healthy women are interviewed and followed for several years to see if cancer develops, radically alters the study results. When such studies have been conducted, researchers have found no link between abortion and future breast cancer. Comparisons illustrate the flaws in earlier studies and suggest their results are not scientifically reliable.

Both a very large Danish study in 1997 and a 2007 Harvard study, among others, showed “no overall effect” on breast cancer risk for women with a history of induced abortions as well as miscarriages. In a 2003 meeting involving over 100 global experts, researchers agreed that “Induced abortion is not associated with an increase in breast cancer risk.” Furthermore, this is “well established,” making the conclusion highly credible. Sorry, anti-choicers.

Groups like the World Health Organization, American Congress of Obstetrecians and Gynecologists, and the National Cancer Institute are on board with this one. The overwhelming scientific evidence does not support claims that abortion causes breast cancer, and members of the anti-choice movement are extremely reluctant to hear or admit this.

Some are remarkably sneaky about twisting the numbers:

Some anti-abortion activists also incorrectly say that young women who choose abortion are at an increased risk for developing breast cancer. These claims are based on evidence suggesting that carrying a pregnancy to term before age 35 may confer a later protective effect against breast cancer. The scientific evidence demonstrates, however, that a young woman who has an abortion is left in the same position as if she had never been pregnant. Claiming that a young woman who has an abortion is at a heightened risk of developing breast cancer is like claiming that a young woman who is abstinent and therefore does not become pregnant is at a heightened risk of developing breast cancer.

The continued distribution of misinformation about abortion and breast cancer is self-serving and dangerous, especially when that information is targeted at children, who may not have the capacity or the skills to perform their own research to dig to the truth of the matter. Capitalizing on a popular cause like breast cancer may be a great way to get attention, but tilting at this particular windmill only reiterates the stereotype that social conservatives are anti-science.

In the midst of ongoing regulatory attempts to tell doctors how to practice medicine in states like Texas where care providers are required to torment patients seeking reproductive health services, laws mandating that doctors should be required to provide false information to patients are deeply disturbing. It’s a profound violation of medical ethics to lie to a patient or subject a patient to a procedure that is not wanted and may be vehemently opposed, yet doctors are being forced to do both these things in order to practice medicine in some states. Simply relocating isn’t an answer, because that leaves thousands of patients without access to needed treatments and services.

Scaremongering about abortion and breast cancer needs to stop. And if members of the anti-choice movement are so concerned about breast cancer risks, they should be taking up actual risk factors, like environmental pollution. Oh, wait, many of them are the same people calling for the shutdown of the EPA.