What is the effect of hormonal contraceptives on exercise? Should I expect to gain weight or have trouble gaining muscle?

Most women are familiar with hormonal forms of birth control, such as oral (the Pill), injected (such as Depo-Provera), or subcutaneous contraceptives (such as Norplant). Transdermal patches, worn on the skin, are also now available. Newer forms of contraceptives, often known as third-generation contraceptives (containing progestagens such as desogestrel or gestodene), appear to have lower risks than older, “second-generation” oral contraceptives (i.e., levonorgestrel), but long term data is not yet available. 

Hormonal contraceptives and weight gain

A 2001 study in the journal Contraception examined the rate of estrogen-related side effects, including weight gain, with low-dose oral contraceptives containing 20 micrograms of ethinyl estradiol. Researchers found no increased rate of weight gain among women taking this medication. It helps to remember that weight can’t be created from nothing: the body needs raw materials (i.e. excess calories) to add more stuff. Thus, good nutrition and regular exercise should be part of your regimen, regardless. 

However, weight can be another issue for women. Some studies suggest that excess body weight can increase a woman’s risk of contraceptive failure. So, keeping fit and staying within a healthy weight range is probably a good idea if you want those contraceptives to do their job! 

Hormonal contraceptives and benefits of working out in the gym

Many women worry that their contraceptives are impeding their gains in the gym. It’s true that women with normal hormonal environments aren’t going to make the same gains as men because men’s natural production of androgens (so-called “male hormones”) is so much higher than women’s. Oral contraceptives also appear to inhibit excess androgen production. But in practice, contraceptives probably won’t noticeably hinder your development of strength, speed, or muscle. 

Exercise helps maintain your bone density

Bone mineral density is often cited as a beneficial effect of estrogen. As we age, our production of estrogen naturally decreases, and this is a risk factor for loss of bone density. Estrogen therapy has been viewed as part of a treatment to help ensure that bones stay dense and strong. If you are combining weight training and other weight-bearing activities (such as walking, running, jumping and punching/kicking things) with healthy levels of estrogen, you have a good chance of keeping good bone density as long as possible. But not all contraceptives are created equal in this regard. Contraceptives containing low doses of estrogen act differently than contraceptives, such as Depo-Provera, containing progesterone-type hormones (depot medroxyprogesterone acetate). Women using Depo-Provera can actually experience loss of bone density with long term use. 

Minimal side effects with recent low-dose hormonal contraceptives

Bottom line: any change to your hormonal environment will have some systematic effect, so treat hormones with respect. But with the most recent forms of low-dose estrogen contraceptives, there’s a good chance that unwanted side effects will be minimal.

Sources: 

Berenson, Abbey, Carmen M. Radecki, James J. Grady, Vaughn I. Rickert, and Angelyn Thomas. “A Prospective, Controlled Study of the Effects of Hormonal Contraception on Bone Mineral Density”. Obstetrics & Gynecology 98: 576-582 (2001). 

Coney P, Washenik K, Langley RG, DiGiovanna JJ, Harrison DD. “Weight change and adverse event incidence with a low-dose oral contraceptive: two randomized, placebo-controlled trials.” Contraception 63 (6): 297-302 (June 2001).

Holt, Victoria, Kara L. Cushing-Haugen, and Janet R. Daling. “Body Weight and Risk of Oral Contraceptive Failure”. Obstetrics & Gynecology 99: 820-827 (2002) 

Thorneycroft IH, FZ Stanczyk, KD Bradshaw, et al. “Effect of low-dose oral contraceptives on androgenic markers and acne”. Contraception 60(5): 255-262 (November 1999).

Krista Scott-Dixon, PhD Contributing Expert

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