On Thursday, the Food and Drug Administration (FDA) said that it cleared Perrigo's once-a-day Opill to be sold without a prescription. It's the first such drug that can be used over-the-counter, and there are no age restrictions.

Hormone-based pills, the most common form of birth control in the United States, have been used by tens of millions of women since the 1960s, with all of them requiring a prescription—until Thursday.

"Today's approval marks the first time a nonprescription daily oral contraceptive will be an available option for millions of people in the United States," Dr. Patrizia Cavazzoni, the head of the FDA's Center for Drug Evaluation and Research, said in a statement Wednesday. "When used as directed, daily oral contraception is safe and is expected to be more effective than currently available nonprescription contraceptive methods in preventing unintended pregnancy."

The pill's manufacturer, Perrigo, called the FDA action a "milestone" as well as a "giant leap for women's empowerment" in a statement posted online after the agency's approval. The firm said that it would make it "accessible and affordable to women and people of all ages."

"Today's approval is a groundbreaking expansion for women's health in the U.S., and a significant milestone towards addressing a key unmet need for contraceptive access," Frederique Welgryn, a Perrigo official, said in the statement.