Birth Control And Weight Gain - Myths And Realities

by Holly Gooding, MD, MSc

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“Will this (any birth control method here) make me gain weight?”

It’s the number one question I get when counseling women about their birth control options, and the number one concern women report in research studies. It’s also a common reason women cite for discontinuing their birth control. But is weight gain related to birth control real?

Like most good questions in clinical medicine, the answer is not straightforward. Comprehensive reviews of the evidence have not found differential weight gain between different contraceptives that contain both estrogen and progestin (“the pill,” “the patch,” and “the ring”). Studies also do not show more weight gain for women taking contraceptives vs. those who aren’t, although placebo-controlled studies are understandably rare in contraceptive research. Reviews of progestin-only methods (Depo-provera, “the shot,” etonorgestrel, “the rod”) do demonstrate more weight gain for women using these methods compared to non-hormonal methods. Mean weight gain was less than 2kg over a year for most studies. Intrauterine devices (IUDs) were not associated with weight gain.

While this evidence is reassuring, some women adamantly report weight gain after starting a new contraceptive. And, these women are accurately reporting their experience; clinic weight measurements back them up. Researchers have tried to sort out who is likely to gain more weight on a given method and why. Some studies find greater weight gain in women already overweight or obese, but others don’t. There is fair-quality evidence that adolescents in particular gain more weight on the depo-provera shot and the etonorgestrel implant. This weight gain might be a barrier to use of these methods despite the fact that they are proven to reduce teen pregnancy and are generally the safest methods for women with other medical co-morbidities. Notably, the levonorgestrel and copper IUDs are long-acting non-estrogen-containing methods not associated with weight gain, making them excellent choices for almost all women, even those concerned about weight gain.

What few women (and likely many providers) appreciate is that most women gain some weight on birth control because most women gain weight over time. But this weight gain is unlikely to be due to the contraceptive method, and is certainly less than the weight gain experienced during pregnancy. Given everything we know about the consequences of unintended pregnancy, I focus my birth control counseling on highly active methods and couple this with healthy diet and exercise counseling as well. If patients discuss weight gain as a barrier to using contraceptives, I point them in the direction of IUDs.

Even if the risk of weight gain is low, failure to discuss the issue with women has important consequences.  If we ignore a woman’s concerns about weight gain with contraceptives, we risk her discontinuing that method and not coming back for care. The right method for an individual woman is the method she will continue taking until she is ready for pregnancy.

Check out youngwomenshealth.org or bedsider.org for contraceptive counseling tools!

About the Author

Holly Gooding is an adolescent and internal medicine specialist who practices at Boston Children's Hospital and Brigham and Women's Hospital.  She provides primary care for teens and young adults and contraceptive counseling services for young women with complex health needs.