CDC finds rise in use of 'morning-after' pill

The pill works by preventing ovulation in the days following unprotected sex. Some believe it also makes the uterine lining less hospitable to a fertilized egg — the basis for criticism by abortion-rights opponents.

According to the CDC, 59 percent of women who used the pill between 2006 and 2010 took it once. Another 24 percent used it twice, while 17 percent used it three times or more.

Most likely to use the medication were young adult women ages 20 to 24. About 1 in 4 had taken the "morning-after" pill over a five-year period, the CDC said.

Abortion-rights groups praised Thursday's report and touted measures like the Affordable Care Act's preventive services mandate, which would allow most women access to birth control with no copay through their healthcare plans.

"Broadening access to affordable birth control options — including emergency contraception — reinforces every woman’s fundamental right to make her own decisions," said Luisa Cabal, vice president of programs at the Center for Reproductive Rights, in a statement.