(CBS) -- The European Medicines Agency is reviewing emergency contraceptives to see if the “morning-after pill” works in women who are overweight or obese.
The agency said in a statement on Friday that it is reviewing a number of emergency contraceptives that contain levonorgestrel as an active ingredient, including Norlevo -- which is identical in formula to Plan B One-Step in the U.S. -- Levonelle/Postinor and Levodonna.
Regulators at the agency, which is similar to the U.S. Food and Drug Administration, will also be looking at ellaOne, which has ulipristal acetate as an active ingredient. EllaOne was allowed to be marketed in Europe in 2009, and is sold as ella in the U.S.
The announcement follows a November 2013 report that some morning-after pills may not be effective for overweight women.
At that time Norlevo’s manufacturer, HRA Pharma, said that European pharmaceutical regulators had approved a request to change the pill's packaging label to warn women that Norlevo was not effective in women over 176 pounds. The warning also stated the pill started to lose efficacy in women over 165 pounds, and is not recommended for women over that weight.
Through independent testing, the company determined that increasing the dosage of levonorgestrel did not help women who weighed more than the recommended limits. HRA Pharma suggested that women who fell under that category should talk to their doctor about other methods of contraception.
A 2011 study in Contraception also showed that obese women who took emergency contraception had a three times higher risk of the pill not working compared to normal-weight women. The risk was higher when the pill contained levonorgestrel, as opposed to ulipristal acetate.
The morning-after-pill refers to a group of medications that are intended to prevent unwanted pregnancy after unprotected sex or if the main form of contraceptive fails. In the U.S., there are three types of morning-after-pills approved for sale: Plan B One-Step, Plan B, and ella.
Plan B One-Step is approved for over-the-counter sale for women of all ages. It is a two-pill medication that works best when taken before three days after sexual intercourse. It will not stop pregnancy if a woman is already pregnant, and it will not harm a fetus.
Plan B One-Step has the same 1.5 mg dose of levonorgesterol as Norlevo.
Plan B is available for sale over-the-counter for women 17 and older, and a prescription for anyone under the age limit. Ella is only available with a doctor’s prescription, no matter the person’s age.
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