Women’s eNews recently reported about an upcoming trial in Fargo, North Dakota, in which a judge will be asked to weight the claims and counterclaims about whether or not abortion contributes to increased risk of breast cancer. Not only are anti-abortion advocates relying on junk science, but they’re own claims are deceptive. Rather than urge women not to have abortions, their advice would be more accurate if they said: have a child before you are 22 or face increased risk of breast cancer. Lets look at the epidemiological evidence before moving on to the biology of abortion, pregnancy and breast cancer.
Anti-abortion advocates always cite the same weak epidemiological data. There are quite a few studies showing that women who have induced abortions have increases risk of breast cancer anywhere from 20 to 30 percent higher than women who do not have induced abortions. The proper reaction to such studies is — big deal.
Those are very low increased risk levels for epidemiological studies — they are so low that it is difficult for even well-designed studies to accurately measure such low levels of risk.
This problem is compounded by the fact that most of these studies suffer from a number of flaws. The most obvious of these, which Womens’ eNews does an excellent job of explaining, is recall bias. Women’s who have breast cancer are far more likely to tell researchers that they had an abortion than are women who do not have breast cancer. A Swedish study, for example, found that women with breast cancer were 50 percent more likely to report having had an abortion than were women without breast cancer. Women’s eNews quotes Lancet Oncology editorial as saying that, “healthy control women have been more reluctant to report on a controversial, emotionally charged subject such as induced abortion, than have patients with breast cancer.”
Of course, a major study involving 1.5 million Danish women that relied on medical records rather than women’s recall. The results? No increased risk of breast cancer at all for women who had abortions compared to women who did not.
The claim that abortion increases risk of breast cancer is nonsense. Sort of. An interesting possibility is that some women may in fact increase their risk of breast cancer if they do something that is increasingly common in the Western world — delay the age at which they have their first child.
A recent study of 100,000 French women, for example, found that women who gave birth to their first child in their 30s were 63 percent more likely to develop breast cancer compared to women who gave birth to their first child by the age of 22. The study also found that women who started having periods the earliest also had a higher risk of breast cancer compared to those who began having periods the latest.
Why should the age at which women have their first child or begin menstruating have anything to do with breast cancer? Dr. Steven Austad offers an excellent summary of the link in his book, Why We Age,
Simply put, estrogen and progesterone increase the risk of breast cancer because they cause the cells lining the milk ducts in the breast to divide prolifically during the latter part of the menstrual cycle, when the body is preparing for pregnancy. When no pregnancy occurs, these newly formed cells die, returning the breast to its original condition. During the next cycle, there is another round of cell division and cell death if no pregnancy occurs.
And of course, the more this cycle occurs, the higher the risk of a mutation that might later develop into breast cancer. But once a woman gives birth, this cycle stops — the cells become permanently differentiated and the monthly division/death process comes to a halt.
So women who want to really reduce their risk of breast cancer should have a child as soon as possible after menstruating. Or if you want to do even better than that, go for a hysterectomy — studies have found that young women who have been forced to have hysterectomies for one reason or another have much lower rates of cancer than do healthy women. This applies to men as well — studies of men who have been sterilized find that they have far lower rates of cancer than men who have not.
If there is any increased risk of breast cancer attendant with abortion, it almost certainly is due to the women using abortion to delay the age at which they first give birth. Women who are on birth control or celibate will also experience the same risk, though this writer has to wonder if abortion activists are prepared to warn all childless women that they are endangering their lives. Would they require the Roman Catholic Church to inform childless women who want to become nuns that they are imperiling their health? Somehow I suspect now.
Sources:
Cancer risks for older mothers. The BBC, February 13, 2002.
Judge to Rule on Abortion, Breast Cancer Link. Margaret A. Woodbury, Women’s eNews, February 17, 2002.
Why we age. Steven N. Austad, 1997.