The US Food and Drug Administration (FDA) has approved the "morning-after" pill without a prescription for women aged 15 and over.
Proof-of-age will be required to purchase the drug, Plan B. The decision comes a month after a judge ordered the drug to be made available to girls of all childbearing ages.
The FDA said its decision was not a response to the court ruling.
Reproductive rights groups approved the FDA move but called for fuller access.
On Tuesday, the FDA said its decision was in response to an amended marketing plan from the drug's maker, Teva Pharmaceuticals, to sell Plan B without a prescription to women 15 and older.
But the move comes days before the deadline to comply with a New York district judge's order to make the drug available over the counter to girls of all childbearing ages.
Obama administration criticised
The judge criticised the Obama administration for imposing an age-17 limit.
In 2011, the FDA said it had concluded 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.
The Obama administration was accused of bowing to pressure from social conservatives.
The reproductive rights group that brought the lawsuit said on Tuesday it will continue its legal fight if need be.
Lowering the age limit "may reduce delays for some young women but it does nothing to address the significant barriers that far too many women of all ages will still find if they arrive at the drugstore without identification", said Nancy Northup, president of the Center for Reproductive Rights.
Editors Note....The American government is approving and promoting immorality.