Health & Medicine

Plan B Morning After Pill may be Less Effective in Women who Weigh More than 165 Pounds

Kathleen Lees
First Posted: Nov 28, 2013 05:49 PM EST

Plan B, known as a popular version of "the morning-after pill" that's typically taken after unprotected sexual intercourse, may not be effective for all women depending on their weight. 

Fortunately, for many women who may be weary of taking the pill, there are other options. However, the question remains-why did it take so long for researchers to discover this problem?

According to Mother Jones, via a Monday report, the French drugmaker of HRA Pharma is working to change the emergency contraceptive Norlevo so that it warns users weighing more than 165 pounds that it may not be effective, and for women 176 or more, the pill is unlikely to work at all.

The pill, which is sold throughout Europe, Canada, Africa and the Middle East contains the same dosage of active ingredients found in Plan B One-Step that's sold throughout the U.S., at 1.5 milligrams of the synthetic hormone levoprogestrel. This hormone helps prevent pregnancy by inhibiting ovulation.

Unfortunately, no label change have been announced yet regarding the Plan B product in the U.S. and any data missing regarding emergency contraception failure and weight in America.

The 2011 research paper on emergency contraception failure discusses the investigation of HRA Pharma label changes that did not emphasize weight and the effectiveness of the product.

In fact, University of Edinburg scientists compared data from trials that looked at the efficacy of two morning-after pills: levonorgestrel and ulipristal acetate, sold in the U.S. as Ella.

Researchers found that the emergency risk of contraception failure was more than three times greater for obese women (those with a BMI over 30) than those in the normal range. It's recommended that overweight women (BMI above 25) should opt for another emergency birth control method, including an alternative pill or an IUD. 

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