Making headlines today is a new study in the Lancet comparing the emergency contraceptives ulipristal acetate and levonorgestrel. Note, however, that the former is approved in the United Kingdom, but not in the U.S. The latter is a form of the hormone progestin, which is approved here.
The study serves as a reminder that emergency contraception is not just the "morning-after pill," often sold as Plan B. It can take a variety of medication forms.
Here's a comparison of the drugs used in this country -- and elsewhere around the globe -- for emergency contraception. Many of them are also prescribed for routine contraceptive purposes. Here's a specific explanation of how those pills are used. The information is from the Office of Population Research at Princeton University.