Plan B less effective in overweight women

European drug regulators warned earlier this week that an emergency contraceptive sold there—with the same hormone formulation as Plan B One-Step—does not work as well in overweight women, which means it’s likely leading to unplanned pregnancies.

The US Food and Drug Administration said in a statement that it is “currently reviewing the available and related scientific information on this issue’’ to determine if they will place a warning label on Plan B One-Step and its generic products similar to the one slapped on the European product called Norlevo.

But reproductive health experts have already decided to advise overweight women—who make up the majority of American women of reproductive age—that they can’t rely on products containing the hormone levonorgestrel such as Plan B One-Step. Instead, they should use other methods when in an emergency situation.


“This news is going to change how I practice,’’ said Dr. Alisa Goldberg, director of the division of family planning at Brigham and Women’s Hospital. She plans to offer overweight patients a prescription that can be filled at any time for a newer form of emergency contraception, ulipristal acetate (ella), which is not available over-the-counter.

Plan B One-Step is available over-the-counter without a prescription and must be taken within 72 hours of unprotected sex.

These women could alternatively get a copper intrauterine device—considered the most reliable emergency contraceptive method—if they come for an office visit within five days of having unprotected sex, Goldberg added.

“The copper IUD is 99.9% effective, not impacted by a woman’s weight, and can be used for birth control for up to 12 years,’’ said Jessica Arons, president & CEO of the Reproductive Health Technologies Project, an activist group based in Washington, DC. For women without insurance, she acknowledged, the $300 to $500 cost of inserting the device could be prohibitive.

Under the federal health law, insurance companies were required last year to start covering IUD’s and other forms of birth control without any copayments, but that mandate is being challenged by some private employers in a case that will be heard by the US Supreme Court.


The warning label on the European product was spurred by a new analysis of a 2011 studyconducted by Scottish researchers, which initially found that obese women who were at least 30 pounds overweight have three times the risk of getting pregnant when using a hormonal form of emergency contraception. The researchers also found that the increased risk was greatest in those who used levonorgestrel.

Norvelo’s French manufacturer, HRA Pharma, did its own evaluation of clinical trial data and found that its product becomes less effective in women who weigh about 165 pounds and was not effective at all in those weighing over 176 pounds.

“The data submitted in Europe to support the label change on Norlevo is HRA Pharma’s proprietary information, and as such, we have not had the opportunity to review it and cannot provide comment on that data at this time,’’ said Denise Bradley, spokesperson for Teva Pharmaceutical, Plan B One-Step manufacturer, in an email. She wouldn’t comment on discussions that Teva is currently having with the FDA about a possible label change.

Other forms of hormonal contraceptives such as birth control pills, shots, and implants do not carry labels warning that their effectiveness depends on a woman’s weight. But concerns that they could be less effective in obese women have been bandied about in the medical community for years.

An April review study conducted by researchers at the Cochrane Colloboration found that excess body weight did not appear to impair the efficacy of these contraceptives, but they also found that high-quality studies involving overweight women were lacking.


“It would be great to have more data on obese women,’’ Goldberg said. “They certainly shouldn’t be excluded from clinical trials.’’

When the FDA first approved Plan B in 1999, it did not require the manufacturer to assess whether the method worked differently for women who were overweight or obese.

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