Contraceptive Pills May Not Prevent Pregnancies in Heavy Women Over 176 Pounds

Various emergency contraceptive pills are not fully effective for women weighing more than 176 pounds.

A European company manufacturing emergency contraceptive pill NorLevo, similar to the contraceptive pill Plan B One Step, will soon be adding a weight-related warning on the pack of the medicine stating that the drug is completely ineffective for women weighing above 176 pounds. The pill is also found to lose efficacy in women weighing above 165 pounds, Mother Jones reported.

This pill, manufactured by HRA Pharma, is sold in many countries like Europe, Canada, India, Australia and various other countries globally, NBC news reports.

The FDA officials are checking various other contraceptive pills' effectiveness in the U.S., the labeling will be changed if required. There are various contraceptive pills available in the U.S. like Plan B One-Step Next Choice, My Way, One Dose, etc.

These pills contain Levonorgestrel, a synthetic hormone, which can block egg fertilization if consumed within 72 hours of having unprotected sex.

Anna Glasier, a professor of obstetrics and gynecology from the University of Edinburgh, had conducted a study  in 2011 regarding what levels of levonorgestrel in i-pills can fail when it comes to functioning in heavier women. This research made HRA Pharma investigate the need to change Norlevo's label, according to Mother Jones.

"..by December 2012, the company had reviewed clinical data on its own and requested permission from a European Union governing body to update its product information," said Karina Gajek, a spokeswoman for HRA Pharma.

"The FDA is currently reviewing the available and related scientific information on this issue, including the publication upon which the Norlevo labeling change was based," Erica Jefferson, an FDA spokeswoman, said in a statement. "The agency will then determine what, if any, labeling changes to approved emergency contraceptives are warranted."

The efficacy of the pill cannot be increased by raising its dosage, Gajek, the HRA Pharma spokeswoman explained.

Plan B One Step, manufactured by Teva Pharmaceuticals, did not pass any comment on this issue, according to media sources.

"New leaflets warning women about the weight limits will appear in every box of Norlevo sold in Europe in the first half of 2014," Mother Jones reported.

The new labeling will be "Studies suggest that Norlevo is less effective in women weighing [165 pounds] or more and not effective in women weighing [176 pounds] or more" and that Norlevo "is not recommended...if you weigh [165 pounds] or more."