European Morning-After Pill Warns It's Not Effective For Women Over 176 Pounds

The manufacturer of Norlevo, a European emergency contraceptive pill identical to widely used American-made pills, reportedly will issue a warning that the drug does not prevent pregnancy for women above a certain weight range.

According to Mother Jones, French pharmaceutical company HRA Pharma plans to attach the caveat to its Norlevo morning-after pill, which inhibits pregnancy and is commonly used after a woman has had unprotected sex. Norlevo will now come with a warning that it is "not effective" for women over 80 kilograms (176 pounds) and is "less effective" in women 75 kg (166 pounds) or more, according to a new leaflet that Mother Jones says will come in every package of the pills within the first half of 2014.

Norlevo is one of the three most commonly used emergency contraceptive brands in France, according to a report by the French National Authority for Health.

Noting that Norlevo has the same chemical structure and dosage as American emergency contraceptive pills including the Plan B One-Step, Mother Jones speculates whether American brands will follow HRA Pharma's lead.

If American emergency contraceptives were to issue a similar warning, emergency contraceptive pills might no longer be considered a viable option for many. The average weight of American women aged 20-29 is 161 pounds, just five pounds shy of the weight at which Norlevo becomes less effective. The average weight of an American woman ages 30-39 is 169 pounds, just above that same cut-off.

"There's no evidence that similar warnings will be popping up here [the U.S.], but our version [the Plan B pill] is formulated with similar levels of the same kind of synthetic hormones as NorLevo," writes Slate, commenting on Mother Jones' report, "meaning there's every reason to believe that women who weigh more than 165 pounds in the U.S. are just as prone to see a decrease in the pill's effectiveness."

This news is concerning, given American's increased usage of drugs similar to Plan B. According to the most recent figures from the U.S. Centers for Disease Control, one in nine American women between the ages of 15 and 44 used emergency contraceptives between 2006-2010. In the past, emergency contraceptive pills generally have been considered 88 percent effective if taken within 5 days after sex, according to Princeton University and the Association of Reproductive Health Professionals' joint contraception information outlet.

As an alternative to emergency contraceptive pills, doctors also recommend using a copper-T intrauterine device (IUD) for emergency contraception. While some women use IUDs as their regular form of birth control, the device is also 99 percent effective as emergency contraception, according to Princeton and ARHP's site resources.

Teva Pharmaceutical Industries Ltd., the manufacturer of Plan B One-Step did not immediately answer The Huffington Post's request for comment. However, The Huffington Post was given the following statement on behalf of Erin Gainer, CEO HRA Pharma:

The effect of a women’s weight on levonorgestrel efficacy was first identified in 2011 during the development of an alternative emergency contraceptive product in the context of a clinical trial. As a result, HRA Pharma has performed further analyses in 2012, which enabled it to put together a safety variation which was presented to some European regulatory authorities at the start of 2013. By sharing the data in this manner it demonstrates a clear obligation by the company to be transparent with the healthcare community and provide regulators with the most up to date information to inform women.

Based on the data, government regulators decided to add the weight warning, Gainer also said.