Levonorgestrel
"So my fiance  and I had unprotected sex on May 6. We weren't scared or had any problems with having a baby. But since we are both still in college we decided that maybe it's not the right time to have one. So later on in the same day, we bought the generic brand of plan b. It was about 40 bucks. I read the symptoms and then took the pill. At that time it was about 5 hours after we had sex. Shortly after I started to have mild cramps for a few minutes but it went away. For a few days my breast became sore, it lasted for a little more than a week. Exactly a week after taking the pill I spotted blood, it was part of the side effects so I didn't worry. Its now May 20th, I got my period a week early. It really works!"