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How Could Abortion Cause Breast Cancer?
At the beginning of pregnancy there are great increases in certain hormone levels (e.g. estrogen, progesterone, and hCG) that support pregnancy. In response to these changes breast cells divide and mature into cells abel to produce mild. Abortion causes an abrupt fall in hormone levels, leaving the breast cells in an immature state. These immature cells can more easily become cancer cells.

Has This Been Proven?
Yes. As of 1/1999, 11 of 12 studies in the USA amd 25 of 31 studies

worldwide, showed that women who experienced an induced abortion had an increased risk of breast cancer. In 1996, Joel Brind, PhD [1], assembled the results of all the studies up to that time. Brind concluded that women who have an abortion before their first fuul-term pregnancy have a 50% increased risk of developing breast cancer while those who have an abortion after their first full-term pregnancy have a 30% increased risk.

What Does it Mean to Have “a 50% increase risk of developing breast cancer”?
A 50% increased risk means a 50% higher risk than someone whould have otherwise. For example, if a person already had a 10% risk of developing breast cancer, the a 50% increase would bring the risk up to 15%.

How Serious a Problem is Breast Cancer?
Breast cancer is the worldwide leading cancer in women and is the most common cause of cancer death for U.S. women age 20-59. In the U.S. every year about 175,000 women are diagnosed with breast cancer and more than 43,000 U.S. women die from this disease.

This means that about 1 U.S. woman of 8 will develop breast cancer at some time in her life and about one-fourth (25%) of such women will die from this disease. Induced abortion, especially at a young age, markedly increases a woman’s risk for developing breast cancer.

This risk is increased even further by other breast cancer risk factors, such as synthetic hormones (including hormonal contraceptives — Birth Control Pill, Norplant, Depo-Provera, etc.), family history of breast cancer, among others.

The U.S. has one of the highest rates of induced abortion and hormonal contraceptive use in the world, especially for young women.

The breast cancer rate in the U.S. is rising, and will likely rise even higher once the latent period (the time it takes for cancer to develop) for these women has passed.

Calculations based on available studies indicate that induced abortion may result in over 46,800 additional cases of breast cancer in the U.S. annually.

Are Some Groups of Women in Greater Danger?
Yes. The research shows that induced abortion increases the risk of breast cancer more for some groups of women than for others. Black women…have higher rates of breast cancer and tend to develop more aggressive cancers. There is also a greater risk in women who have had abortions if they were under age 18 at the time, if they do not have any more children after abortiong, or if they have a family history of breast cancer.

What is the risk for young women?
Janet Daling noted in 1994 [2] that women younger than 18 who had an abortion experienced a 150% increased risk of developing breast cancer. This became an 800% increased risk if they had their abortions between the 9th and 24th week of pregnancy.

What if there has been Breast Cancer in My Family?
Women who have a family history of breast cancer and choose to have an abortion are at very high risk of developing breast cancer. Andrieu et al (1994) [3] found that women who had a family history of breast cancer and had 2 or more induced abortions had a 600% increased risk of breast cancer as compared to the rest of the population.

Daling et al (1994) [2] noted that women who had an abortion prior to age 18 and had a positive family history of breast cancer had an infinitely increased risk of developing breast cancer compared to youn women who had a family hsitory of breast cancer and had not had an abortion.

Daling also noted that women who were 30 or older at the time of their abortion and had breast cancer in their family history had a 270% increased risk.

But isn’t Pregnancy & Childbirth More Dangerous than Abortion?
No. The risk of breast cancer is increased by abortion and the suicide risk [and the risk of clinical depression and maternal mortality in general] is much higher after an abortion. On the other hand, the risk of ovarian cancer is decreased after a full-term pregnancy. Because of changes in these 3 risk factors alone [without even considering clinical depression and other maternal mortality causes], abortion is many times more hazardous in the long-run than carrying a child to term.

1. Brind J, Chinchilli M et al. Induced abortion as an independent risk factor for breast cancer: a comprehensive review and meta-anaylsis. J Epidemiol Community Health. 10/1996; 50: 481-496.
2. Daling J, Malone K et al. Risk of breast cancer among young women: relationship to induced abortion. JNCI. 1994; 86: 1584-1592.
3. Andrieu N, et al. Familial risk of breast cancer and abortion. Cancer Detection and Prevention. 1994; 18:51-55.
5. Clarck RM, Chua T. Breast cancer and pregnancy: the ultimate challenge. Clinical Oncology. 1989; 1:11-18.

[excerpted from the brochure “Breast Cancer Risk from Abortion” by Chris Kahlenborn MD; Chris Kahlenborn MD is an internist and has authored Breast Cancer, Its Link to Abortion and the Birth Control Pill.]



A typical 15 year old American girl has a 10% lifetime risk of breast cancer. If she gets pregnant in her teens and has the baby she reduces her risk to 7.5%. However, if she has an abortion, her risk of breast cancer rises to 15% (assuming she has at least one child in her 20’s). If the abortion causes permanent infertility her and/or for other reasons, she never has another pregnancy, her risk rises to 30%. [Source: Brinton LA, Hoover R, Fraumeni IF, Ir. (1983) Brit. J. Cancer. 47:757-62.]