What are side effects of taking morning after pills frequently? every ry month (last month i used them twice), is it safe to use it again tday? to prevent pregnancy, after last night's unprotected sex with my boyfriend

Excessive PlanB use: Plan B can alter the menstrual bleeding for the cycle in which Plan B was taken, and sometimes the next cycle too. One should be sure to check a home pregnancy test 3 weeks after sex, because Plan B works most of the time, but not all the time. Be sure to have a Plan A (good contraception method) in place, so that Plan B is never needed again. Plan B is not to be one's main, primary birth control.