Over-the-counter emergency contraception pills may not work as well for women who are over a certain weight, CNN.com reports. French pharmacists studied the European drug Norlevo, which is identical in chemical composition to the American Plan-B One-Step. They found that the drug began losing its effectiveness in women who weighed more than 165 pounds, and it showed a complete “absence of effectiveness” when a woman exceeded 176 pounds. Their research further supports a 2011 observational study, which found that obese women had three times the risk of getting pregnant after taking emergency contraception pills than women with a normal body weight. In response to these new findings, all Norlevo pills sold in Europe will now come with a warning label saying the pill is “not recommended” for women over a certain weight. The U.S. Food and Drug Administration says it has begun reviewing the research to see if similar American label changes are also necessary.

To read the article, click here.