The drug RU-486 is taken after sexual intercourse. It blocks implantation, and in this sense it prevents pregnancy_.
| 1. | like spermicidal foam |
| 2. | in a manner similar to tubal ligation |
| 3. | like the familiar birth control pill used for the last 30 years |
| 4. | by blocking progesterone receptors in the uterus, thus preventing progesterone from maintaining pregnancy |