The European Medicines Agency says it has started a review of emergency contraceptives to see if they are less effective in overweight women.
In November, French drug maker HRA Pharma announced its morning-after pill didn't work in women heavier than 80 kilograms and changed its labels to warn patients after consulting with European regulators.
In a statement today, the EMA said it would evaluate new data suggesting that a high body weight could compromise the effectiveness of the morning-after pill.
HRA Pharma's Norlevo contains levonorgestrel, the same active ingredient in other medicines including ellaOne, Levonnelle and Levodonna.
The morning-after pill can be taken up to 72 hours after unprotected sex. It works by preventing ovulation or fertilisation of an egg.
