Combined Oral Contraceptives and Weight Gain
Combined oral contraceptive pills (COCs) do not cause clinically significant weight gain in reproductive-age women. 1, 2
Evidence from Placebo-Controlled Trials
The highest quality evidence comes from three placebo-controlled randomized trials, which found no causal association between combination oral contraceptives and weight gain. 2, 3 This represents the strongest level of evidence available, as these trials directly compared COCs to placebo rather than to other hormonal methods.
- No large effect on weight is evident when COCs are compared to placebo, and most comparative trials between different COC formulations show no substantial difference in weight changes. 2, 3
- The American Academy of Pediatrics explicitly states that weight gain has not been reliably linked to combined hormonal contraception. 1
Understanding Normal Weight Patterns
A critical context often overlooked: reproductive-aged women naturally gain weight more rapidly than other age groups, with an average weight gain of 6.3 kg over 10 years, independent of contraceptive use. 4 This background weight gain is frequently misattributed to contraceptive methods.
Screening and Monitoring Recommendations
Weight (BMI) measurement is not needed to determine medical eligibility for COCs because all methods can be used among women across all weight categories. 5 However, measuring baseline weight may be helpful for monitoring changes and counseling women concerned about perceived weight effects. 5
- Women with obesity are generally not more likely to gain weight with COCs compared to their normal-weight peers. 1, 4
- Discontinuation rates due to weight gain do not differ between COC formulations when studied. 2, 3
Formulation-Specific Considerations
While most COC formulations show no difference in weight effects, some specific progestins may have unique properties:
- Drospirenone-containing COCs (e.g., 30 mcg ethinyl estradiol/3 mg drospirenone) may have a more favorable effect on body weight due to antimineralocorticoid activity that prevents salt and water retention. 6
- Starting with low-dose pills (≤35 mcg ethinyl estradiol) is recommended as first-line for combined oral contraceptives. 1
Critical Pitfall to Avoid
Do not discontinue effective contraception based on weight misperceptions, as the risk of unintended pregnancy far outweighs minimal or nonexistent weight effects from COCs. 1 Many women perceive weight gain from COCs when objective evidence does not support this association. 7
Contrast with Injectable Contraceptives
It is essential to distinguish COCs from depot medroxyprogesterone acetate (DMPA), which is associated with weight gain in a subset of users:
- DMPA users gain significantly more weight (average 6.2 kg) compared to COC users (2.3 kg), non-users (2.8 kg), and discontinuers (2.8 kg) over 4-5 years. 8
- Weight gain at 6 months with DMPA is a strong predictor of future excessive weight gain with ongoing use. 1
- Adolescents with obesity using DMPA are at higher risk for weight gain compared to obese COC users. 1, 4
Counseling Approach
When addressing weight concerns with patients considering COCs:
- Explain that placebo-controlled trials show no causal link between COCs and weight gain. 2, 3
- Acknowledge that natural weight gain occurs in reproductive-age women regardless of contraceptive use. 4
- If weight neutrality is a primary concern, copper IUDs, barrier methods, and surgical sterilization are the most weight-neutral options. 1, 4
- Reassure that COCs have numerous noncontraceptive benefits including decreased menstrual cramping and blood loss, improvement in acne, and no negative effect on long-term fertility. 1