Abortion, Miscarriage, And Other Factors Influencing Fewer Risk Of Breast Cancer

Pregnancy, of course, is not the only experience of a woman's life that changes her estrogen and progesterone levels. Hundreds of millions of women of reproductive age take the contraceptive Pill, which is usually a combination of estrogen and progesterone, as the pill alters a woman's hormonal balance to prevent pregnancy. Taking the pill raises a woman's risk of breast cancer after menopause by about 25%.

Many women further take estrogen replacement therapy to deal with intimate dryness, hot flashes, and mood swings after the menopause. In women who have not yet reached the age of 65, estrogen replacement therapy raises a woman's risk of breast cancer about 35%. After the age of 65, however, most doctors believe the risk of cancer is lower. In the Women's Health Study, taking a combination of estrogen and progesterone replacement therapy, instead of taking estrogen alone, was found to cause even greater risk of breast cancer.

Beginning menstruation relatively early in life and experiencing menopause relatively late in life increase a woman's cumulative exposure to estrogen and her lifetime risk of breast cancer, because these women will experience more menstrual cycles during their lifetimes (unless other factors prevent them from menstruating, including repeated pregnancy, prolonged breastfeeding, and the use of hormonal contraceptives). Women who have their first periods before the age of 13 or who continue menstruation after the age of 50 have an approximately 100% greater risk of breast cancer. (It is important to understand that though that number is huge, it does not mean every woman who meets these conditions will definitely develop breast cancer!)

Women who have had uterine or ovarian cancer are at greater risk of developing breast cancer, and women who have previously had any form of breast cancer, even if "in situ," non-metastatic breast cancer are at greater risk of developing metastatic, potentially fatal breast cancer later in life. There is some disagreement among experts as to whether women who have large breasts (breast hyperplasia) or who have fibrocystic breast disease are at greater risk of cancer.

But what about abortion and miscarriage?

Does failing to carry a baby to term somehow increase the risk of breast cancer later in life?

Although opponents of abortion maintain that women are somehow "punished" for failing to carry a baby to term, the medical evidence suggests that women who undergo miscarriages or induced abortions are only as likely to develop cancer as women who have not become pregnant at all. There were two studies in the 1990's that suggested a link between abortion and cancer, but later examination of the research found that the investigators sought out replies from women whose moral views supported their own. Whatever one believes about the morality of abortion, the scientific fact is that it does not "cause" breast cancer — although an abortion certainly does not prevent it, either.

Women who have children also enjoy lower rates of ovarian cancer — but it is important to put the risk of cancer in perspective. In the United States of America, about 1 woman in 8 is eventually diagnosed with breast cancer. Even doubling her risk of breast cancer only increases that probability to 1 in 4. On the other hand, even women who have had babies, who have never used hormonal birth control, and who never had abortions can develop the disease. Cancer can strike almost anyone, although it is possible to lower the risk.

No woman will have as many children as possible simply to reduce her risk of developing breast cancer — high-risk women are far more likely to opt for a double mastectomy. However, women who experience more than a few pregnancies do a lot of hard work and place their body through a lot of risks, so the thought of being "rewarded" with a lower cancer risk may be comforting.