how do i know plan b is working? should i be worried about pregnancy?

Hello Anonymous,

Thank you for reaching out to us with your concerns about Plan B and the potential for pregnancy. Try to relax. I will try to help you.

Beginning with the facts, Plan B is most effective if taken within within 72 hours after you've had unprotected sex, Plan B One-Step can reduce the risk of pregnancy by up to 89%.

You take Plan B One-Step about 16 hours after the incident. So, it is about 95% effective.

Depending upon where you were in your menstrual cycle, Plan B works by:
preventing or delaying ovulation
interfering with fertilization of an egg
possibly preventing implantation of a fertilized egg in the uterus by altering its lining.

After taking Plan B, you may have some unexpected bleeding. It should go away by the time of your next period. However, it is possible that Plan B One-Step may cause your next period to be heavier or lighter than usual. It may also come earlier or later than is normal for you. If you don't get your period within three weeks, take pregnancy test to make sure you're not pregnant.

Regards,
Maryann