Prescription-free birth control pills will be available across the United States later this month, widening access to contraception at a time when abortion rights have been drastically curtailed.

American-Irish maker Perrigo Company announced Monday that its Opill has "shipped to major retailers and pharmacies and will be available on shelves nationwide," available in one-month and three-month packs for $19.99 and $49.99 respectively. It will also be available on Opill.com.

Over-the-counter (OTC) birth control has long been backed by major medical organizations as a way to reduce barriers to contraception access, with more than 6.1 million births in the US each year unintended, according to official data.

"We champion the right of women and people to determine their own sexual health journey and the availability of Opill over-the-counter is truly a historic moment of which our entire organization can be proud," said Perrigo Executive Vice President Triona Schmelter.

Opill, which was cleared last year by the Food and Drug Administration for sale without prescription, is known as a "mini pill" because it contains progestin only, and works by thickening mucus in the cervix to stop sperm reaching an egg.

Preserving access to contraception has proven politically divisive following the conservative-led Supreme Court's decision to revoke the national right to abortion in 2022.

Twenty-one states banned or moved to restrict abortions to limits tighter than before Roe v Wade, the case law that previously upheld the constitutional right to terminate a pregnancy.

Republicans in Congress also blocked Democrat-backed legislation that would have codified individuals' right to access contraception, an issue that has taken on more urgency as conservative-run states define personhood in new ways.

Alabama's top court last month said that frozen embryos should be considered children, though the state's legislature quickly moved to pass a bill protecting clinics from legal liability if such embryos were inadvertently damaged or destroyed.

Over-the-counter birth control is backed by major medical organizations, including the American College of Obstetricians and Gynecologists (ACOG), the American Medical Association and the American Academy of Family Physicians.

Much of Asia, Africa and Latin America allow OTC birth control. The UK joined the club in 2021, but prescriptions are still required in much of mainland Europe including France, Germany, Spain and Italy, according to "Free the Pill" which tracks the issue.