The Obama administration will comply with a judge's order to allow women and girls of any age to purchase emergency contraception, ending its efforts to restrict the drug's availability.
The reversal on the politically sensitive issue means that anyone, including young girls, will soon be able to purchase the popular Plan B One-Step morning-after pill over the counter, without a prescription.
President Barack Obama's administration had fought against U.S. District Court Judge Edward Korman's order seeking to make the drug more widely available after a more than decade-long court fight, warning of health and social dangers.
In a letter to U.S. District Judge Edward Korman, U.S. attorneys said the Food and Drug Administration was dropping its appeal.
"To comply with the order, FDA has asked the manufacturer of Plan B One-Step (PBOS) to submit a supplemental application seeking approval of the one-pill product to be made available OTC without any such restrictions," the agency said in a statement.
"Once FDA receives that supplemental application, the FDA intends to approve it promptly."
Levonorgestrel-based emergency contraception contains the same active ingredients as birth control pills but at higher doses, and may prevent pregnancy if taken within 72 hours after unprotected intercourse.
The Center for Reproductive Rights, which brought the latest lawsuit, hailed the FDA's "significant step forward" but criticized the administration for "unjustifiably" preventing generic, more affordable brands of emergency contraception to be made widely available.
"We are pleased that women should soon be able to buy Plan B One-Step without the arbitrary restrictions that kept it locked behind the pharmacy counter when they needed it most urgently," the center's president and CEO Nancy Northrup said in a statement.
"But we will continue to fight for fair treatment for women who want and need more affordable options."
In April, the FDA approved Plan B One-Step for girls aged 15 and up -- reducing the age restriction by two years.
But the move only applied to one brand of emergency contraception, and required that it be security-tagged to avoid theft and only sold over the counter in stores that have a pharmacy.
It followed an order by Korman for the government to make levonorgestrel-based emergency contraception available without prescription or point of sale restriction.
Korman had slammed Health and Human Services Secretary Kathleen Sebelius's decision overruling the FDA to require teens under 17 to obtain a prescription as "politically motivated" and "scientifically unjustified."