Accidents can occur, which is why emergency contraception exists as a secure and efficient method to prevent pregnancy for up to 5 days following unprotected intercourse.
There's more than one kind of emergency contraception. What will work best for you will depend on a few factors: when you last had sex, your weight, and whether you’re breastfeeding.
The Plan B pill works best when you take it within 3 days after unprotected sex. Like all morning-after pills, take Plan B ASAP after unprotected sex.
A levonorgestrel morning-after pill — like Plan B One Step, Take Action, My Way, Option 2, Preventeza, AfterPill, My Choice, Aftera, and EContra — can lower your chance of getting pregnant by 75–89% if you take it within 3 days after unprotected sex.
You can take Plan B and other levonorgestrel morning-after pills up to 5 days after unprotected sex. But sooner is better — the longer you wait to take it, the less effective it is.