A federal judge in New York has ordered the United States government to make the morning-after contraceptive pill freely available to girls of all ages within 30 days.
Judge Edward Korman on Friday struck down an Food & Drug Administration rule requiring girls 16 and under to have a prescription for the pill.
He said the restriction was "arbitrary, capricious and unreasonable".
The case was brought by the Center for Reproductive Rights.
The BBC reports that previously, the Obama administration insisted that only older girls and women could have the pill without a prescription.
In 2011, the FDA said it had concluded that the "morning after" pill could be safely used by girls of child-bearing age.
But in an unprecedented move, Health and Human Services Secretary Kathleen Sebelius overruled the agency.
She said there was not enough evidence from all potential ages to support removing over-the-counter restrictions. President Barack Obama said he supported the decision.