The Arizona law, which took effect in April, requires medical abortions to be performed according to U.S. Food and Drug Administration protocols, which restrict medical abortions to the first seven weeks of pregnancy and require women to make three visits to a doctor.
While supporters of that type of law say they are concerned about women's health and safety, the American Medical Association and American College of Obstetricians and Gynecologists -- which supported the challenge to the law -- said evidence-based methods developed since the FDA issued its protocol are both safer and less expensive.
In Arizona, almost half of abortions are performed using medication instead of surgery. Providers had been doing them up to nine weeks with only two visits to a doctor.
"As a leading health care provider to women in Arizona, we want to protect women's health and safety, but these restrictions go against more than 13 years of medical research," said Bryan Howard, president of Planned Parenthood of Arizona. "It's 2014 -- it's well past time medical decisions be left between a woman and her physician."
The 9th Circuit said in its ruling that Arizona provided no evidence that "the law advances in any way its interest in women's health."
Josh Kredit, a lawyer for the Center for Arizona Policy, which helped craft the law, said medical abortions involve a "dangerous drug" that should only be administered as specified by the FDA. He said he expects a further appeal.