Abortion and breast cancer: a forged link.

A major weapon of the anti-abortion movement is its scare-mongering claim that having an abortion significantly increases a woman's risk of breast cancer--the "ABC link." This allegation is grossly deceptive and just plain false. A substantial weight of evidence counters the ABC link, and a recent international scientific consensus has rejected it.

Unfortunately, this doesn't stop anti-abortionists from presenting the ABC link as an undisputed fact, even manufacturing the lie that half of all abortion patients will go on to develop breast cancer. This is what anxious women were advised in 1996 when they called the toll-tree number on east coast subway advertisements that featured the dire warning: "Women Who Choose Abortion Suffer More and Deadlier Breast Cancer!" In spite of new research that largely refutes the ABC link, almost all anti-abortion websites still trumpet the claim without reservation, and scientific-sounding ads hyping the ABC link have appeared in newspapers.

The latest tactic is lawsuits aimed at forcing abortion providers to inform patients of the bogus link. It's all part of the neverending anti-abortion war, and although anti-abortionists want us to believe they're fighting the battle to save women, what they're really doing is turning women into frightened pawns in a strategic campaign against abortion.

Anti-abortionists promote the alleged ABC link because seventeen out of thirty-seven scientific studies that have examined the link showed a small overall increase in breast cancer risk for women who have abortions. These studies had serious flaws, however. In particular, most were older case control studies that suffered from a major bias: they relied on women sell-reporting their abortion history Women with breast cancer are more likely to tell the truth about past abortions because people with serious illnesses are motivated to report their medical history accurately to facilitate their treatment and recovery But control groups of healthy people have less incentive to report honestly and, in fact, many women keep quiet about past abortions since it's a private and sensitive issue.

It's well established that in medical case control studies, patients tend to disclose their histories more fully than healthy control groups (a phenomenon called recall bias), and a recent study has confirmed abortion underreporting by healthy women. According to Radha Jagannatha in the November 2001 American Journal of Public Health, within a randomly selected group of Medicaid recipients in New Jersey, only 29 percent of those who had a Medicaid billing for an abortion actually admitted to the abortion in a reproductive health survey. Other studies on underreporting have found that only 35 percent to 60 percent of actual abortions are reported in surveys. What this means is that the detection of an ABC link by self-report studies is untrustworthy. Women with breast cancer only appear to have had more abortions than healthy women.

The best studies of the alleged link are called historical cohort studies because they rely on complete medical records for entire populations of women, over decades. This means researchers have accurate statistics from a large sample from which to calculate exactly how many women suffered breast cancer, how many had abortions, and which ones had either or both. No cohort study has shown evidence of an ABC link, at least for abortions performed in the first trimester.

The definitive cohort study on the ABC link was conducted by the Danish Epidemiology Science Center at Statens Serum Institute in Copenhagen and reported in the January 9, 1997, New England Journal of Medicine. Researchers M. Melbye, M. Wohlfahrt, J. H. Olsen, M. Frisch, T. Westergaard, K. Helweg-Larsen, and P. K. Andersen used data from detailed government medical registries of 1.5 million Danish women, which recorded all cases of breast cancer or legally induced abortion since 1973. The researchers found zero increased risk of breast cancer for women who have abortions by the fourteenth week of pregnancy. (The study left open the question of whether a risk may be present for late abortions performed after eighteen weeks, but the rarity of these abortions would render any such risk statisically less problematic.)

Attempts by the anti-abortion movement to refute the Danish study have failed. Anti-abortionist Joel Brind accused the study authors of making gross errors in their research design. In response the authors said, "We find [Brind's] argument self-contradictory and based on fundamental misconceptions about the cohort design." Although they corrected Brind's specific misunderstandings, their rebuke failed to modify Brind's position; he continues to propagate the same criticisms to his exclusive audience, the anti-abortion movement.

Brind, a professor of biology and endocrinology at New York City's Baruch College, is a tireless proponent of the ABC link. He has devoted an entire website--www.abortioncancer.com--to the issue. The website states that Brim "has written and lectured extensively" on this topic since 1992, but his lecturing is confined essentially to the antiabortion speaker circuit, and he has published only one peer-reviewed research paper on the supposed connection between induced abortion and breast cancer. This 1996 paper, "Induced Abortion As an Independent Risk Factor for Breast Cancer: A Comprehensive Review and Meta-Analysis" (Journal of Epidemiology and Community Health, October), has been heavily criticized. Brind pooled the data from twenty-three studies on the ABC link and came up with a 30 percent increase in risk. However, most of the studies he included were those flawed by reporting bias, so it was a classic case of "garbage in, garbage out." Brind's work has been supplanted by a December 2001 review of twenty-eight studies of the ABC link by British researcher Tim Davidson, who concluded in the Lancet Oncology there was "insufficient data to justify warning women of future breast-cancer risk when counseling them about abortion."

There simply is no known mechanism that would cause the alleged ABC link. Brind speculates that abortion suddenly interrupts the estrogen surge, leaving rapidly growing breast cells in an undifferentiated state and more vulnerable to carcinogens. However, this hypothesis has no empirical support. Besides, how would one then explain the fact that studies show no link between miscarriage and breast cancer, as anti-abortionists acknowledge? Brind claims the "raging-hormones-cut-short" problem doesn't affect miscarriage, since most miscarriages are caused by a lack of pregnancy hormones. Not so--the majority of miscarriages are actually caused by genetic defects in the egg/embryo, and other causes; only an estimated 10 percent or so of miscarriages are caused by hormonal deficiencies. This means there is probably no significant difference between the effects of miscarriage and abortion--so if miscarriage doesn't lead to an increased risk of breast cancer, then, of course, neither would abortion.

For the sake of argument, let's suppose that Brind's ABC link is real. What would it really mean? He claims that abortion may boost the risk of breast cancer by 30 percent, but this increase is not really that significant. For example, the risk is 200 percent to 300 percent higher for a woman whose mother or sister had breast cancer alter age fifty. Even this well-established risk factor is considered moderate by scientists. In comparison, the alleged ABC link barely qualifies; even if it's real, the risk is close to negligible. To put it another way, the National Cancer Institute estimates the current risk of breast cancer to be one in 2,525 for a woman in her thirties; if that risk were increased by 30 percent, it would mean one in 1,942 women would get breast cancer.

Second, correlation doesn't equal causation, which means some other factor could be responsible for any increased breast cancer risk, thus confounding the study results. For example, women with a first full-term pregnancy after age thirty face a breast cancer risk two to three times higher than women with a full-term pregnancy before age twenty. If a study included many women who had aborted their first pregnancy when they were young, effectively postponing motherhood, we might find a correlation between abortion and breast cancer, but delayed childbearing would be the more probable cause of the increased risk.

Anti-abortion "researchers" are notorious for confusing correlation with causation, which is showcased by a new study, privately funded by a British anti-abortion group. The "study"--published by lone author Patrick Carroll and not peer reviewed--blames thirty years of legalized abortion for rising rates of breast cancer in some countries. Dismissed or ignored are many other probable causes that have also proliferated in the last thirty years--including delayed childbearing, smaller family size, better cancer-screening methods, environmental contaminants, obesity in mid-life, and the use of oral contraceptives and hormone replacement therapy.

Many reputable organizations have released position statements or articles discounting the ABC link, and citing the Danish cohort study and other reliable studies in support. Such groups include the American Cancer Society, the National Cancer Institute, the National Breast Cancer Coalition, the World Health Organization, the Center for Reproductive Law and Policy, the Alan Guttmacher Institute, the Planned Parenthood Federation of America, and others. On its website (cis.nci.nih. gov/fact/3_53.htm), the National Cancer Institute says: "Although it has been the subject of extensive research, there is no convincing evidence of a direct relationship between breast cancer and either induced or spontaneous abortion." After reviewing the research on the ABC link, the World Health Organization's online article (www.who.int/inf-fs-/ en/fact240.html) concludes: "Therefore, results from epidemiological studies are reassuring in that they show no consistent effect of first trimester induced abortion upon a woman's risk of breast cancer later in life." Impervious to reality, however, Brind and other anti-abortionists make the preposterous claim that these groups are conspiring in a "pro-abortion cover-up" of the ABC link.

Anti-abortionists are now taking their crusade to legislatures and courtrooms. Laws have been sponsored in about two dozen states to force abortion providers to inform patients of the supposed breast cancer risk, and so far two states--Montana and Mississippi--have passed them. In 1999, anti-abortionists launched a "false advertising" lawsuit against a North Dakota abortion clinic for distributing a pamphlet saying the ABC link is unsupported by medical research. The case is currently before the courts, and a new suit has recently been filed by three California women against Planned Parenthood for "misleading" women about the ABC link.

Raising the stakes even higher, a dubious lawsuit was settled in Australia in September 2001, in which the plaintiff had sued her abortion provider for not informing her of the alleged risk of "psychiatric damage" from abortion (there's actually little or no risk). Tacked onto the lawsuit was the additional "failure" to warn of an increased risk of breast cancer. Settled confidentially out of court, the case highlights the disconnect between law and science. Anti-abortionists are naively touting the settlement as "proof" of the ABC link, but lawsuit settlements are the crafty negotiations of lawyers, have nothing to do with science, and are incapable of establishing scientific facts. Defendants are often pressured to settle out of court for expediency's sake, not because they're in the wrong.

More lawsuits like the Australia case are on the way. Behind them lies the enduring modus operandi of the anti-abortion movement--demonizing abortion providers and intimidating women out of abortions. But given the current evidence against the ABC link, it would be irresponsible for health professionals to advise abortion patients of any alleged risk. Anti-abortionists' fear-mongering promotion of the ABC link is reprehensible as well as fanatical. Although aware that their evidence is highly disputed, anti-abortionists continue to advise women, without qualification, that having an abortion puts them at great danger of breast cancer. For a pregnant woman faced with the traumatic, life-changing decision of whether or not to have a baby, such hypocritical posturing to advance a political anti-abortion agenda is callous in the extreme.

Joyce Arthur is a freelance and technical writer from Vancouver, British Columbia. An activist in the abortion rights movement, she is the editor of the Canadian newsletter, Pro-Choice Press.