how long does the emergency contraceptive Plan B work for?

I want to know if she can still get pregnant about a week after taking it.

It use to be 72 hours, however that has been changed. It’s now effect up to 120 hours after sex, which is 5 days.

That said, if she took plan b a week ago, then had unprotected sex again, she needs to seek out plan b once again. Although, you also need to use a reliable form of birth control, be it hormonal birth control or properly using condoms. Taking Plan B isn’t birth control, it’s for emergency only. It’s not even that close to 100%, birth control or condoms are much more reliable, plus taking large doses of hormones like this so often isn’t good for her system, hormones, or cycle.