Bleeding after Plan B does not confirm that the medication worked or rule out pregnancy. Spotting or irregular bleeding is a common side effect, and your next period may come earlier or later than expected.
Implantation bleeding can occur in early pregnancy, but bleeding alone cannot confirm pregnancy. A pregnancy test is the most reliable way to know.
Plan B (levonorgestrel) works best when taken as soon as possible after unprotected sex and is FDA-approved for use within 72 hours. Other emergency contraception options, such as ulipristal acetate (ella), can be used up to 120 hours, or 5 days, after unprotected sex.
If your period is more than 1 week late, take a home pregnancy test and contact an OB-GYN or primary care provider. A doctor may also order a blood hCG test or, when appropriate, an ultrasound to confirm a pregnancy.
Seek medical care promptly if you develop severe lower abdominal pain or persistent or heavy bleeding, especially if your period is late. These symptoms may need to be evaluated for an ectopic pregnancy or another cause.