Without comment, the high court lifted a temporary stay blocking a federal judge's ruling that Missouri officials had to drive the woman to a clinic to have the procedure over the weekend.
Late Friday, Justice Clarence Thomas had granted a temporary stay at that ruling, but Monday's high court decision was unanimous.
Missouri's law forbids spending tax dollars to facilitate an abortion, but the federal judge took the position that the prison system in Missouri was blocking her from exercising that right.
The high court's order means that she can receive the procedure.
The woman had planned to have the procedure done on Saturday, but Thomas granted the temporary stay late Friday, blocking the ruling by U.S. District Judge Dean Whipple. Thomas then referred the case to the full court.
The woman has not been identified. Her attorney, James Felakos of the American Civil Liberties Union, said in court papers that she is running out of time because she is 16 weeks to 17 weeks pregnant, and Missouri bars abortions after 22 weeks.
She has said she will borrow money for the abortion from friends and family but cannot afford to pay for transportation to a clinic to have it done.
The court fight was over those costs, estimated at $350 plus fuel for two guards to accompany the woman on the 80-mile trip from her cell in Vandalia to a St. Louis clinic.