THE EUROPEAN MEDICINES AGENCY is to investigate whether increased bodyweight impairs the effectiveness of some popular brands of the morning-after pill.
The review is a result of data published in November that suggested emergency contraception could be less effective in women above 80 kg (12.5 stone).
The review will look at whether the warning labels on the emergency contraceptive medicines should be changed.
The brands being reviewed include those that that contain the hormone levonorgestrel, such as NorLevo, Levonelle/Postinor and Levodonna.
Emergency contraceptives containing levonorgestrel can be used up to 72 hours after unprotected sexual intercourse or contraceptive failure and act by blocking or delaying ovulation.
Another prescription-only brand of the morning-after pill ellaOne, which can be used up to five days after unprotected sex, is also to be reviewed.
The review comes after the makers of NorLevo added the following information to the product about its effectiveness in November:
In clinical trials, contraceptive efficacy was reduced in women weighing 75 kg or more, and levonorgestrel was not effective in women who weighed more than 80 kg.
The review is being conducted by the Committee for Medicinal Products for Human Use, its opinion will then be forwarded onto the European Commission.