Like all birth control, emergency contraception is not 100% effective. We recommend getting a pregnancy test 2-3 weeks after taking emergency contraception, such as Ella or Plan B.
Ella emergency contraception can prevent pregnancy up to 5 days after sex. It is more effective than other morning-after pills, but you need a prescription to get it, which means you need a provider to give it to you. Ella lowers your chances of getting pregnant by 85 percent if you take it within 5 days after unprotected sex.
Plan B works best when you take it within 3 days after unprotected sex. You do not need a prescription for Plan B, it is available on a walk-in basis. Plan B can lower your chance of getting pregnant by 75-89% if you take it within 3 days after unprotected sex.