Question: is the morning after pill less effective if overweight?
Answer: Women with a body mass index (BMI) of 25 or higher experienced decreased efficacy, and the pill stopped working entirely in obese women with a BMI of 30 or higher. In fact, obese women that took levonorgestrel were slightly more likely to become pregnant, 5.8%, than women who did not take EC at all, 5.6%.