Levonorgestrel
"So, there's always that story where the condom broke. My story is the same story. My boyfriend and I were using protection because I can absolutely not get pregnant, and then the worst thing happens; it breaks. right after we were done we noticed and immediately started freaking out. Who wouldn't in our case? about 20-30 minutes later I took the pill, but I still had to wait 16 days for my period. A little less then a week, though, I started! I didn't seem to have any side affects, but that's just me. I have never been more happy to see mother nature making her daily visit."