Emergency contraception: How it works, how effective it is and how to get it

Plan B is one brand of the emergency contraceptive levonorgestrel, which works by delaying ovulation. It is sold over the counter at pharmacies, but is often kept in locked boxes or is only accessible by asking a pharmacist. (Justin Sullivan/Getty Images)

With abortion getting banned or heavily restricted in many states, reproductive health experts say it's important that both patients and providers know the options available when it comes to emergency contraception. For many people, it's a final safety net against unintended pregnancy.

Many advocates suggest women and all those who can get pregnant have emergency contraception on hand before they need it. "It's going to be really, really important for people living in states where that's the last chance they have and they really need to prevent pregnancy," says Cynthia Harper, a contraception researcher and professor of obstetrics, gynecology and reproductive sciences at the University of California, San Francisco.