Does Excess Body Weight Reduce Efficacy of Oral Contraceptives?

Overweight as a cause of contraceptive failure is a concern for clinicians and patients alike; however, even as U.S. obesity rates rise, data are lacking because contraceptive studies typically exclude women who are overweight. Limited findings suggest that efficacy of non-oral delivery modes (such as patches and implants) is reduced in heavier women, but data on oral contraceptives (OCs) have been mixed.

In a retrospective, open-label, industry-supported study, researchers evaluated the effect of body weight on unintended pregnancy in users of a low-dose, extended-regimen OC (LoSEASONIQUE) consisting of 100 µg levonorgestrel and 20 µg ethinyl estradiol (EE) for 84 days followed, by 10 µg EE for 7 days. Of 1736 participants (age range, 18–35…