Study: Fertility Drugs Don’t Increase Breast Cancer Risk for Most Women


A new study 30 years in the making finds that fertility drugs do not raise most women’s risk for breast cancer.

Women who have trouble getting pregnant are often given drugs containing estrogen to stimulate ovulation either as a stand-alone fertility treatment or as part of in vitro fertilization. Experts have been concerned that prolonged exposure to estrogen as well as increased ovulation could put women at higher risk for breast cancer. The new study, published in Cancer Epidemiology, Biomarkers & Prevention, should put at least some of those fears to rest.

Researchers at the National Cancer Institute analyzed the medical records of 9,892 women in the United States who had been evaluated for infertility between 1965 and 1988. About 38 percent of the women in the study used the fertility drug clomiphene, marketed under the name Clomid, and about 10 percent used another class of drugs known as gonadotropins, though often in conjunction with Clomid. Over the decades that followed, 792 cases of breast cancer were diagnosed among the women in the study, but analysis found that women exposed to these drugs were no more likely to be diagnosed than women who had not taken either class of medication.

There were some exceptions to the results, however. Women who were exposed to 12 or more cycles of Clomid had a 70 percent higher risk of developing breast cancer compared to women not exposed to the drug at all. However, these women got much more of the drug then women taking it today. The current normal dose of Clomid is half that of what it used to be, and guidelines now limit women to three to six cycles of the drug.

Another small subset of women were also at increased risk. Women who took gonadotrophins together with Clomid and were still never able to become pregnant were about twice as likely to develop breast cancer as women who had not taken either drug. However, the researchers suspect that for these women, some of the increased risk is likely tied to the underlying problem that caused their persistent infertility.

The researchers say that their results are “generally reassuring” but caution that they need to keep watching these women, as risk of the breast cancer goes up with age. Louise Brinton, chief of the Hormonal and Reproductive Epidemiology Branch at the National Cancer Institute and lead author of the study, told the Plain Dealer, “Even though we’ve had 30 years of follow-up, it’s still pretty early in the game. The women are still quite young.”

Still, some experts were pleased with the results. Dr. Kurt Barnhart, president of the Society for Reproductive Endocrinology and Infertility, told Reuters Health, “It’s reassuring that if women desire pregnancy and unfortunately have infertility that they can undergo treatment without modification of their overall risk for cancer later.”

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  • red_zone

    So in short, all the claims of ‘birth control increases your risk of cancer’ are, if not completely invalidated, then significantly over-exaggerated with very little basis by today’s standards of care

    It’s going to be a lot harder for those railing against contraception of any kind to validate their claims with actual proof. And harder to twist it.

    • Melinda Hampton

      This article isn’t about birth control.

      • Shan

        Both birth control and fertility drugs involve increased exposure to estrogen. It’s not that far of a stretch to compare the two.

        • Melinda Hampton

          There is a huge difference in the amount and duration.

          They aren’t even remotely comparable.

          But since you think that this study is comparable, surely you agree with me that birth control pills should be made as otc medication.

          • Shan

            You’re trolling. I’m not interested.

          • Melinda Hampton

            trolling for you to explain your thought that fertility drugs and birth control pills are somehow the same? yeah, ok.

          • Shan

            Yes, that’s exactly what you’re doing. If you can frame a question politely and without any strawman bullshit, I’d be glad to entertain it.

          • Melinda Hampton

            OK, let’s recap.

            1. Red zone made a factual error about the article being about birth control (and not fertilization drugs). She was wrong.

            2. I corrected her.

            3. You objected to my correction.

            4. To prove my point that they are in fact different, I try to ask you about your opinion on why other estrogen increasing medication is treated different. You got flustered. You called me a troll.

            Fair recap?

          • Shan

            “Fair recap?”

            Nope. Like I said, try again without the strawman bullshit.

          • Arekushieru

            For one, red-zone said nothing about the article being about birth control. Go back and re-read what she actually said. Not ONCE did she imply that she thought the article was about birth control. Simple extrapolation could be the reason for her conclusion, you should try it some time, it might improve your reading skills.

            For two, Shan never said that fertility drugs and birth control pills were exactly the same, therefore rendering your argument for birth control to be OTC just like Emergency Contraception entirely moot.

            For three, actually Shan implied EXACTLY that. ‘Increased’ is not a measurement. And ‘that far of a stretch’ implies some distance, therefore differences. Again, reading comprehension, people.

            For four, Shan did not get flustered.

            Fair recap?

            Btw, flagged and ignored.

          • lady_black

            OK. Clomid is not an estrogen, and may actually compete with estrogen in it’s effects. It acts on the pituitary gland to stimulate ovulation through a series of hormonal events involving FSH and luteinizing hormone.

          • Melinda Hampton

            Why are you replying to me.

            Shan was the one who said ivf drugs and ocp drugs were basically the same.

            oh look…my comment was deleted. I wonder why…maybe because when i called out red zone, i was correct.

          • lady_black

            Fertility drugs are not “IVF drugs.” IVF is for people who have mechanical obstacles to conceiving in the usual manner. Most users of fertility drugs will, in fact, not use IVF.

          • lady_black

            I’m replying to you because this is a public forum. I need not refrain from speaking until spoken to, because frankly, you aren’t my superior. Your comment was deleted because you’re trolling, not because you’re correct. And don’t bother condescending to me again by telling me to take a physiology class. I’m a nurse and damned well know what’s in Plan B. It acts by hormonal manipulation to mimic pregnancy so that ovulation is suppressed temporarily.

          • Melinda Hampton

            No, my comment was deleted because it made red zone look like an idiot…and we wouldn’t want that. She is a regular.

          • goatini

            Troll comment was deleted because it’s trolling

          • Arekushieru

            Do you actually read anyone’s replies to you? If not, way to prove you’re just a troll. OCP drugs include far more than just EC, and you should know that. Birth control covers far more than just EC. Other than that, we have already SHOWN you how your claim that Shan said fertility drugs and birth control is basically the same, is FACTUALLY incorrect.

          • goatini

            “Melinda” has been trolling here for at least several weeks.

          • Melinda Hampton

            Fuck off abusive troll. What did I ever say to you?

          • goatini

            Flagged for verbal abuse and trolling. The flagged abusive troll has been trolling here for several weeks.

          • expect_resistance

            Yep, noticed that.

          • goatini

            And the VRH troll usually shows up to support the Hampton troll. S/h/it’s right on schedule today.

          • Mindy McIndy

            Not in the least. Not every woman can take every pill out there. There are different pills with different formulas in them. In fact, some people can’t take birth control pills at all and have to use IUDs, implants or the Depo Provera shot. Do you think all of those should be OTC as well?

          • Melinda Hampton

            I’m not saying that people shouldn’t follow up with their doctor. But you should do that with a lot of otc medication. Aspirin can cause liver damage. NSAIDS can cause GI bleeds. Drinking to much water can kill you. That doesn’t mean that water should be a prescription medication.

            The argument was once made that emergency contraception should remain sa prescription medication. Using Shan’s argument that every drug that increases levels of estrogen are roughly equivalent and therefore compatible, How is otc EC ok, and not otc bc pills?

          • Mindy McIndy

            It’s the convenience factor. in many places, it is difficult to get into your doctor in an emergency situation like that, so having it over the counter makes it easier. That doesn’t mean you shouldn’t consult with your doctor after taking it, but if you can’t get into your doctor for a week and the pill needs to be taken in 48 hours, how is that going to help anybody?

          • Melinda Hampton

            So now you’re placing convenience over women’s health?? FFS SMDH

          • Mindy McIndy

            Would you rather her get pregnant and have an abortion?

          • Melinda Hampton

            Well well now….so you’ve now admitted that you’ll excuse any health risk of emergency contraception if it prevents pregnancy and therefore abortion…but not for birth control pills.

            interesting…I wonder why that is.

          • Mindy McIndy

            It has been deemed safe by the FDA to sell over the counter. Regular birth control pills have not. What do you not understand about this?

          • Melinda Hampton

            Yeah, but Shan thinks all meds that increase estrogen are the same so…

          • Shan

            Nope.

          • Melinda Hampton

            Then why did you take offense to me telling red zone that the article isn’t about OCP?

          • Shan

            I didn’t.

          • Melinda Hampton

            might want to go edit your comment then

          • lady_black

            Plan B does not contain, nor increase estrogen. It contains levonorgestrel, which is a synthetic progesterone, so it may alter your menstrual cycle. Typically, a “period” may occur off schedule, due to progesterone withdrawal. For the purposes of resuming oral contraceptives, it should be treated as a period. with day one being the day bleeding occurs.

          • Melinda Hampton

            you should take a physiology class

          • lady_black

            I have.

          • VonRecklingHause

            I know why…because if it’s OTC, insurance won’t pay for it and this is what it is all about.

          • Shan

            That’s a terribly tired trolling tactic, too.

          • Jennifer Starr

            Yeah, you’re right. That’s an argument that I’m getting mighty tired of.

          • Arekushieru

            Then why aren’t we trying to make emergency contraception prescription medication if that is what our issue is? Hmm, hoisted by your own petard, again? Too bad, so sad.

          • VonRecklingHause

            How much you wanna bet emergency contraception coverage is mandated by Obamacare in a couple of years?

          • Arekushieru

            Uh, go back and re-read my question, please. My question had nothing to do with whether emergency contraception coverage would be mandated by Obamacare.

          • lady_black

            Wrong. It’s because time is of the essence.

          • Arekushieru

            I don’t. Sounds PRECISELY like it’s because one is for, let me spell it out for ya, E.M.E.R.G.E.N.C.I.E.S. (y’know, like the name says) and the other is for non-emergency use. Things get a LOT more ‘inconvenient’ when there is a specific time frame in which they need to be taken than if there is not. Kthx.

          • Shan

            “Using Shan’s argument that every drug that increases levels of estrogen are roughly equivalent and therefore comparable”

            That wasn’t my argument. You are still trolling.

          • lady_black

            Emergency contraceptives do not contain estrogen, and are made for emergency use only. Meaning they aren’t to be taken day after day for extended periods. Plan B One-Step is OTC to increase access to it, because *time is of the essence.* I’m very sure that the package insert discloses this, among other things such as 1) Plan B will not protect against STDs and 2) if a patient should be on a long-term contraceptive, they should seek medical advice.

          • lady_black

            OCPs are safe for use under medical supervision.

  • Arekushieru

    So, since CBJ_Uno is voting Melinda Hampton’s comments up, I take it they’re fine with discriminating against the LGBT community as well as having one form of health care covered while denying another type, which is also discrimination. Are they also against abortion? Because, since contraceptives decrease the rates of abortion, that would make them even MORE of a hypocrite.