How Plan B Works

Women have turned to Plan B One‑Step for years when their birth control plan A didn’t work out. Plan B is emergency contraception that helps prevent pregnancy before it starts when taken within 72 hours after unprotected sex or birth control failure. We recommend that stores carry Plan B right on the shelf so that it’s available to anyone who needs it. Regardless of where women buy it, there’s no prescription or ID needed—and no age requirement, either.

What Plan B is:

• Progestin‑only emergency contraception that works by temporarily delaying ovulation

  Similar to birth control pills, Plan B works by delaying the release of an egg from the ovary.

• The same active ingredient as regular birth control pills—just at a higher dose

  It’s a single tablet that contains levonorgestrel 1.5 mg, an ingredient that’s been safely used in many birth control pills for decades.

• Won’t hurt the chances of getting pregnant later on

  While it does help prevent pregnancy after unprotected sex, it won’t affect a woman’s ability to get pregnant later on.

What Plan B isn’t:

• Not regular birth control

  Since Plan B only stays in the body for a short amount of time, it’s not meant to be used as a regular birth control method.

• Not an abortion pill

  It won’t affect or harm an existing pregnancy

• Won’t protect against HIV/AIDS or other STDs

  Plan B will help prevent pregnancy before it starts, but it won’t prevent any sexually transmitted diseases. With that in mind, women should always use a barrier method, like condoms, to prevent STDs.

Did you know?

Unlike other emergency contraception options, women can and should resume their regular hormonal birth control immediately after taking Plan B.

Why? Plan B contains the same active ingredient as many popular birth control pills—levonorgestrel—just at a single, higher dose.