"when i read all of these reviews, on every page, i couldn&#039;t find one that was someone&#039;s experience with plan b while on the birth control pill. so i&#039;ll leave mine. i missed one pill the week i had intercourse but i had also missed so many pills last month i wanted to be safe. my doctor advised me to continue taking my birth control while taking the plan b. i had no side effects at all. my cycle came 3 days late and it was a bad one. it started with a day of light spotting. it was very heavy compared to most."