Plan B can cause side effects like irregular bleeding and is 95% effective if taken within 24 hours after unprotected sex.

Light spotting before your period isn't always a cause for concern. But in some instances, it can be a sign of implantation ...

If the emergency contraception plan b messed up your cycle for months, here's when to expect things to get back to normal, per an OB/GYN. While totally safe, one of Plan B’s main (albeit temporary) ...