Morning after pills
Emergency contraception pills, aka morning-after pills, work by preventing or delaying ovulation. The sperm waits in vain for 5 days and cannot fertilize the egg. If your ovulation started and conception occurred before you’ve taken the pill, it won’t work.
There are 2 types of emergency contraception pills:
– Ulipristal acetate. It is effective up to 120 hours (5 days) after unprotected intercourse.
– Levonorgestrel. It is effective up to 72 hours (3 days) after unprotected intercourse.
For both pills, it is important that you take them as soon as possible.
Pills containing ulipristal acetate are generally the most effective. However, if you need emergency contraception because you forgot to take your “normal” pill, it seems that levonorgestrel may be more effective, especially if taken within 3 days after the forgotten pills and intercourse. The action of ulipristal may be weakened by regular contraceptive pills you took earlier.
Can the morning after pill delay your period?
The morning after pill can delay your next period. You should not have unprotected sex until the next menstruation (use a condom or don’t have sex at all until your next period comes).