By Steve Olafson

OKLAHOMA CITY (Reuters) - A judge blocked a new Oklahoma law on Wednesday that would have prohibited women in the state from having medication-induced abortions to end unwanted early-term pregnancies.

The law had been scheduled to go into effect on November 1, but state District Judge Dan Owens issued a temporary restraining order in a victory for abortion rights advocates.

Nova Health Systems, which operates a clinic in Tulsa, and the nonprofit Oklahoma Coalition for Reproductive Justice had filed a lawsuit to block the law.

They will ask Owens to issue a permanent injunction to kill the law, said attorney Michelle Mohaved of the New York-based Center for Reproductive Rights, which is representing the plaintiffs. She said she was "thrilled" by the ruling.

Oklahoma lawmakers approved the law barring drug-induced abortions earlier this year, saying they were seeking to protect women's health. A similar law in North Dakota has also been blocked in the courts and remains under review.

The Oklahoma law's sponsors have said that abortion-inducing drugs have led to the deaths of eight women in the United States.

But Mohaved disputed that, saying the deaths were not caused by the medications. Opponents to the law said the legislature's ideological opposition to abortion created an unconstitutional law that jeopardized women's health.

The two-pill abortion medication known as RU486 has been legally available in the United States since 2000, and by 2008 accounted for about a fourth of U.S. abortions performed before nine weeks gestation, according to the Guttmacher Institute, an abortion rights think tank.

The two drugs - mifepristone and misoprostol - can be obtained from a physician, and are typically used to terminate pregnancies of less than eight weeks.

Oklahoma Attorney General Scott Pruitt said the judge's decision to block the law was unfortunate for the state and for public health.

"We are confident that we will prevail in protecting Oklahoma women and families from dangerous drugs," he said in a statement.

(Editing by Corrie MacLaggan and Cynthia Johnston)