The new law banning abortions at 20 weeks starts Thursday. (HPZ/Flickr)

The ban prohibits abortions starting at 20 weeks of pregnancy except in medical emergencies, which is a change from the state's current ban at viability.

U.S. District Judge James Teilborg said the state provided "substantial and well-documented" evidence that an unborn child has the capacity to feel pain during an abortion by at least 20 weeks. He also said the new law is constitutional because it does not prevent women from making the decision to get an abortion.

Arizona is one of 10 states to enact a type of 20-week ban. 

Republican Governor Jan Brewer signed the measure into law in April.

According to CBS News, the Center for Reproductive Rights and another group that challenged the law plans to file an emergency appeal of Monday's decision with the 9th U.S. Circuit Court of Appeals.

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