Under the appellate court's decision, the FDA does not have to lift restrictions on the sale of the one-step morning-after pill while its appeal is heard.
The controversy began when U.S. District Court Judge Edward Korman ordered the FDA to knock down all age and point-of-sale constraints that previously applied to emergency contraception.
That order came down on April 5. The FDA's appeal is being heard on an expedited basis.
The morning-after pill helps to prevent pregnancy in the days following intercourse, and is considered equivalent to abortion by opponents of abortion rights.
Conservative groups say the drug should not be available over the counter to young women. Abortion-rights supporters say unrestricted access to emergency contraception is vital to women's health.