The condom broke. Or you missed a pill. As you learn about your options. you come across information that states Plan B doesn’t work for people who weigh more than 165 pounds. That’s because in 2011,  some studies indicated that Plan B Emergency Contraception (containing levonorgestrel) wasn’t effective for women over a certain weight. This prompted the European Medicines Agency (the FDA equivalent in Europe) to approve a label change warning women of the possible reduced efficacy. This label change then prompted the Food and Drug Administration (FDA) to conduct its own review over whether the Plan B emergency contraception available in the US needed an updated label as well.

In light of their review, today the FDA concluded that the data concerning the effectiveness of levonorgestrel (LNG) EC (the most commonly used emergency contraception) in women who weigh more than 165 pounds or have a BMI of more than 25 kg/m2 was inconclusive. This means that the FDA doesn’t believe a change in the labeling is warranted at this time, but that more research is needed to better understand the relationship between weight and the effectiveness of LNG-containing EC.

The National Women’s Health Network also believes that further research on the potential relationship between body weight and EC needs to remain a top priority. Without this crucial information, women are forced to play guesswork with their contraception. Women should be aware of all of their options related to contraception and pregnancy, and well-informed to make the best decision for their health care needs.

While the verdict is out on whether weight affects how well EC will work for a particular woman, we know that timing does matter; it is important to take emergency contraception as soon after unprotected sex as possible to improve efficacy. Women, and particularly women with a higher body weight, should be encouraged to use the most effective options (the copper IUD or ulipristal acetate [ella]). If these options aren’t easily accessible, or are unacceptable to an individual, no woman should be denied or discouraged from using levonorgestrel EC because of her weight. Women must have autonomy in all aspects of their health care, but especially in decisions related to their reproductive health.

To learn more about the link between emergency contraception and body weight, check out the March/April issue of The Women’s Health Activist.