Is there a reason to believe that the emergency contraceptive levonorgestrel (LNG), most popularly known as Plan B, may not be as effective in women that weigh more than 165 pounds or have a body mass index > 25kg/m2? According to FDA in a Question and Answers document (here) posted on the Center for Drug Evaluation and Research (CDER) webpage yesterday, the FDA states that “[c]urrent information about whether levonorgestrel (LNG) emergency contraceptives (ECs) work as well in women who weigh more than 165 pounds or have a BMI above 25 kg/m2 is conflicting and limited. The FDA does not believe that a change in the labeling for LNG EC products is warranted at this time. There are no safety concerns that preclude use of LNG ECs in women generally, and the FDA continues to believe that all women, regardless of how much they weigh, can use these products to prevent unintended pregnancy following unprotected sexual intercourse or contraceptive failure.”
The FDA goes on to discuss that, in 2013, a French manufacturer provided data to European regulators that implied that their product did not work for women who weighed more than 80 kg or 176 lbs. Based on that data, the EU regulators permitted a change in labeling. However, after a complete review of the data they found that “the data were too limited and not robust enough to conclude with certainty that contraceptive effectiveness is reduced with increased body weight.”. FDA’s review of the data concluded the same thing and, thus, at this time, FDA is not recommending any label change. “Because the currently available data are limited and conflicting, the FDA believes further research by the manufacturers of these products on the possible impact of weight or BMI on effectiveness should be a priority.”
Based on the evaluation of the additional research, there could be a Plan B for Plan B at least for a subset of women if the data ultimately supports a label change.