Morning-after pill ineffective for heavier women

Turns out, that morning-after pill may not be so effective at preventing pregnancy – at least not if you weigh more than 165 pounds.

The European manufacturer of an emergency contraception pill identical to the Plan B pill is warning women that the drug loses effectiveness in women who weigh more than 165 pounds, according to a Mother Jones article.

And for women who weigh more than 176 pounds? For them, the pill is completely ineffective, according to the article.

The manufacturer of the European drug Norlevo is adding the weight warning to the packaging.

Some of the most popular morning-after pills in the U.S. – including Plan B One-Step, Next Choice One Dose, My Way and others – have a dosage and chemical makeup identical to Norlevo, according to the article.

plan b

Plan B One-Step is the only emergency contraceptive drug in the U.S. available to women of all ages without a prescription.

American manufacturers don’t currently have weight warnings on their contraceptives. And a spokeswoman for Teva Pharmaceutical Industries, which manufacturers Plan B, declined comment for the Mother Jones article. (Manufacturers of the other brands, which are generic versions of Plan B, didn’t comment either.)

The pills use a compound called levonorgestrel to prevent pregnancies. The European drug manufacturer began investigating the need to change the drug’s label after research published in 2011 showed pills using levonorgestrel are prone to fail in women with a higher body mass, according to the Mother Jones article.

It’s unclear whether drugmakers can formulate a levonorgestrel pill for women who weigh more than 165 pounds.

Related fun fact: The average American woman weighs 166 pounds, according to the Centers for Disease Control and Prevention.

Marissa Harshman

Marissa Harshman

I'm the health reporter for The Columbian newspaper in Vancouver, Wash. I started at The Columbian -- my hometown newspaper -- in September 2009. Reach me at or 360-735-4546.

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