Does your weight affect how well your birth control works?

Your weight will not impact how effective your birth control is for almost all types of birth control. Two exceptions are the patch and emergency contraception.

For the patch, Xulane or Zafemy, may be less effective if you weigh more than 198 pounds. Twirla, the lower-dose patch option, may be less effective at preventing pregnancy if your BMI is 25 or greater, and it should not be used at all if your BMI is 30 or greater because of decreased effectiveness and a potentially increased risk of blood clots.

When it comes to emergency contraception, over-the counter levonorgestrel-based emergency contraception, like Plan B One-Step, Next Choice One Dose, and others, may not be as effective in people who weigh 165 pounds or more. Prescription EC pill, ella, may not work as well if you weigh 195 pounds or more. Some types of IUD work as EC and they are equally effective no matter how much you weigh.