The US Supreme Court has preserved access to a commonly used abortion pill, ruling the drug can remain available while a legal case continues.
In a split decision, it also rejected restrictions on mifepristone implemented by a lower court, essentially maintaining the status quo.
The future of the drug was called into question after a Texas judge sought to invalidate its long-standing approval.
The case could have wide-ranging implications for abortion access.
It comes after the Supreme Court – which has a 6-3 conservative supermajority – overturned Roe v Wade in June last year, ending the nationwide guarantee to abortion and giving states the power to ban the procedure.
With Friday’s ruling, the mifepristone case now returns to the lower 5th Circuit Court of Appeals.
It is likely that the case will come before the Supreme Court once again, setting up the most significant ruling for reproductive rights since Roe was overturned.
Mifepristone is part of a two-drug regimen that now accounts for more than half of abortions in the country. It has been used by more than five million women in the US to end their pregnancies.
It was first approved by the US Food and Drug Administration (FDA) more than 20 years ago after four years of review.
The FDA also placed mifepristone in a category of 60 drugs that are regulated under a system of extra restrictions and regular evaluations.
Its safety and effectiveness is supported by mainstream medical organisations including the American College of Obstetrics and Gynaecologists (ACOG) and the World Health Organization (WHO).
But earlier this month, Texas court judge Matthew Kacsmaryk ruled to suspend the FDA approval of mifepristone, saying the FDA had violated federal rules that allowed for the accelerated approval of some drugs, and had erred in its scientific assessment of the drug.
Mr Kacsmaryk’s preliminary decision came after a group of anti-abortion health professionals launched a case challenging the safety of mifepristone.
US President Joe Biden’s administration appealed, and a divided appeals court said mifepristone could remain available, but with certain restrictions, while the appeal was under way.
Among the restrictions imposed by the 5th Circuit Court of Appeals was a limit on sending the pills by mail, effectively requiring in-person visits. These restrictions have now been overturned by the Supreme Court, for now.
The ruling in the Texas case came just minutes before a further ruling from a judge in Washington state ordered the FDA to make no change to the drug’s availability and preserving access to mifepristone in 17 US states.
Two of the Supreme Court’s conservative members, Justice Clarence Thomas and Justice Samuel Alito, dissented publicly to Friday’s decision, which came in a single paragraph, issued hours before a midnight deadline.
Mr Thomas provided no reasons for his dissent, while Mr Alito wrote that the Supreme Court has been criticised in the past for issuing emergency orders, called the “shadow docket” by critics.
In a statement, Mr Biden said his administration “would continue to defend FDA’s independent, expert authority to review, approve, and regulate a wide range of prescription drugs”.
“The stakes could not be higher for women across America,” he said. “I will continue to fight politically-driven attacks on women’s health.”