Levonorgestrel
"I took Next Choice One dose after unprotected sex in late Dec 2014. I just had ended my period a couple days prior and probably was not ovulating but took it just in case. After taking the pill I experienced tiredness the first day. Awful cramps for a couple days after and then started to bleed for about 4 days which seemed like a period. This is a common side effect I read. I was also told if you bleed after the pill, that usually means it worked. My period ended up coming last night which is 8 days after my normal period date. I was stressed the whole time waiting for my period to come. Finally it's here. This pill works!"