The morning after pill can help prevent pregnancy by delaying ovulation. If you’ve had unprotected sex or experienced contraceptive failure, the morning after pill can delay the release of your egg so that any sperm in your vagina will have nothing to fertilise and will die off before ovulation does occur.
The morning after pill only works by delaying ovulation. If you ovulate in between having unprotected sex and taking the pill, then it will not be effective. The morning after pill cannot interrupt an existing pregnancy and it does not cause an abortion.
There are two types of emergency hormonal contraception available in the U.K. ellaOne contains ulipristal acetate, and some other morning after pills contain levonorgestrel.
ellaOne® is the most effective morning after pill* and can be taken up to 5 days (120 hours) after unprotected sex or contraceptive failure, although we recommend taking it as soon as possible. Levonorgestrel can be taken up to 3 days (72 hours) after unprotected sex or contraceptive failure.
*verify at ellaOne.co.uk/verify.