France Contraceptive

Since the French contraceptive maker HRA Pharma alerted women that its morning-after pill is ineffective when taken by women who weigh more than 80 kilograms or 176 pounds, label changes were phased in. (Remy de la Mauviniere/Associated Press)

Emergency contraceptives or "morning-after" pills will soon carry a warning about their reduced effectiveness in heavier women, Health Canada says.

The regulator said it’s asked four companies selling emergency contraceptives to add labels to their packaging to alert women that the pills are less effective in women weighing 165 to 176 pounds and are not effective in women over 176 pounds.

Doctors say women can take emergency contraceptives, ideally within 72 hours after unprotected sex or a contraceptive accident, such as a condom breaking.

These emergency contraceptive brands are available without a prescription in Canada:

  • Next Choice (Cobalt Pharmaceuticals Company).
  • Norlevo (Laboratoire HRA Pharma).
  • Option 2 (Perrigo International).
  • Plan B (Teva Women’s Health Inc.)

Health Canada said it’s evaluated new data from Laboratoire HRA Pharma and approved the company’s submission to update the packaging and labelling for Norlevo with the new warning over the next several months.

The regulator has also asked the other three Canadian manufacturers to update the labels and packages for their products.

The pills contain higher levels of levonorgestrel than standard oral contraceptives. They work by preventing ovulation or fertilization of an egg.

In December 2013, French drug maker HRA Pharma warned its morning-after pill may be less effective in women who weigh more than 165 pounds and the medication is ineffective in women who weigh more than 176 pounds.

Women who weigh more than 165 pounds are advised to speak to a doctor or pharmacist about alternative methods of emergency contraception.

During the transition, current packages will stay on pharmacy shelves.