The Pill: Class One Carcinogen

Dear Louis, Thank you for trying to get the word out- and for your understanding that to put all of the data into a short sound bite is very difficult. It is especially difficult because we cannot perform a randomized controlled trial with birth control, and other types of studies can have significant bias. There are large population studies that show the birth control pill does not harm women, but we have been wrong before with less potent artificial hormones in hormone replacement therapy. The burden of proof of safety should be on the drug companies if lower doses cause cancer and heart disease, but it seems the burden of proof of harm is on those who have moral objection.

The article that you forwarded to us laid out very well some of the known, noncontroversial risk factors for breast cancer- early menarche, late menopause, or early terminated pregnancy that gives the woman a high estrogen load without the protective effect of maturing her breasts to a state that is more resistant to carcinogens. Oral contraceptives give a very high estrogen load (I have seen estimates of 5-15 times more potent than what the body makes). Rather than just nine months, the woman may be exposed to this load for years before having her first child. It is in this population that the risk is the highest- by the largest meta-analysis the risk was increased to 1.44.

Whereas many are not afraid to say alcohol, early menarche or hormone replacement therapy is a cancer risk, the Pill tends to have a very protected status in our culture, and despite a higher estrogen effect, is not commonly listed. It seems our culture would not know what to do if the Pill was ever taken away- so much is built on it’s acceptance that it is consciously or unconsciously protected. There is the financial aspect of drug companies, but I think that’s only a relatively small part. Even the educational system in med schools, where science at it’s best should be taught, are not training doctors in the healthier alternatives- and typically teach that the Pill is safer than pregnancy- which is not comparing apples to apples.

Even though people may choose to smoke, they do so knowing it may cause cancer. Many women believe that the pill is basically healthy since it is a medication prescribed by a physician, and the side effects are often minimized when a woman is initially prescribed the Pill. Although some may ignore the classifications of carcinogens by the WHO, I use the statement to make people at least stop and wonder why- since most view it as basically safe, and have never even heard that it can cause cancer. But those brief ‘sound bites’ always need follow up with explanations of the physiology and the limitations of our current research studies. For a more detailed evaluation of the studies, I highly recommend Dr. Chris Kahlenborn’s book “Breast Cancer: It’s link to abortion and the birth control pill” which can be purchased from CANFP and elsewhere.

Again, I appreciate your efforts to spread the news that contraceptives are unhealthy for women. Any suggestions on how to make the message clearer will be greatly appreciated!

Blessings! Lynn Keenan, MD Clinical Professor of Medicine, UCSF/Fresno