Morning-after pill may not work if you weigh more than 80kg

NEW research has found that emergency contraception - the morning-after pill - may not work for women who weigh more than 80kg and the drug loses its effectiveness for women who weigh more than 75kg.

The investigation, by a French pharmaceutical company, has lead HRA Pharm, the European manufacturer of the pill NorLevo to include a warning on every packet sold from the first half of  next year.

NorLevo is sold in Australia.

There is no suggestion that hormonal contraceptives such as the daily contraceptive pill is less effective in women weighing more than 75kg.