(Adds details on injunction in fifth paragraph)
By Verna Gates
BIRMINGHAM, Ala., Aug 4 (Reuters) - A U.S. judge on Monday ruled unconstitutional an Alabama law that threatened to close three of the state's five abortion clinics, while a trial opened in Texas with an abortion rights group trying to overturn restrictions imposed in that state.
A number of abortion clinics have closed in recent months due to laws passed in 11 U.S. states requiring doctors who perform abortions to have admitting privileges at a nearby hospital. Supporters say the measure protects women's health while opponents say it is an unnecessary regulation designed to force clinics to shut down.
U.S. District Judge Myron Thompson ruled Alabama's law imposed an undue burden on a woman's ability to choose to have an abortion by making it unnecessarily difficult to obtain the procedure.
"The evidence compellingly demonstrates that the requirement would have the striking result of closing three of Alabama's five abortion clinics," the judge wrote.
There was a temporary injunction already in place allowing the clinics to operate. That temporary injunction will remain in effect until the court meets with all parties to determine final relief.
Admitting privileges generally allow a doctor who is approved by a hospital to admit a patient for treatment at that hospital. Lawmakers in some states require abortion doctors to have admitting privileges at a hospital within 30 miles (48 kms) of their clinic.
Abortion rights groups maintain such a provision is unwarranted because abortion complications are rare and tend to be similar to those of a miscarriage, which can be treated by emergency room physicians. The provision also places an undue burden on women in rural areas where medical facilities are sparse.
Alabama Governor Robert Bentley, a Republican, said he was disappointed in the ruling because it would erode protections for expectant mothers.
"Abortion is a fundamental assault on the sanctity of innocent human life, and I believe that it should only be done as a last possible effort to save the life of the mother," Bentley added.
A federal appeals court last week ruled that Mississippi's law requiring abortion doctors to have local hospital admitting privileges was unconstitutional. The law, passed in 2012, would have shut down that state's only abortion clinic.
Mississippi's decision will probably have more impact than the Alabama decision, according to Elizabeth Nash, state issues manager for the Guttmacher Institute, which tracks abortion rights issues.
"The really big takeaway from Mississippi was that a state cannot abdicate its responsibility for abortion services to another state," Nash said.
Measures similar to Alabama's 2013 law are in place in other states including Texas, whose law was upheld in March by a federal appeals court, which said the regulation supports continuity of care.
A federal court in Austin, Texas, on Monday heard arguments in a trial brought by the Center for Reproductive Rights against a new set of regulations that go into effect in September requiring abortion providers in the state to meet the same building requirements as ambulatory surgical centers.
Jan Soifer, a lawyer for the abortion rights groups, said in opening statements the provision was costly, uncalled for and would results in clinics with a smaller patient base to close because they cannot afford the construction costs.
Lawyers for the state argued the Texas law was medically justified and has been supported by courts. (Reporting by Verna Gates; Additional reporting by Jon Herskovitz in Austin, Texas, and Lisa Maria Garza in Dallas; Writing by Jon Herskovitz and Colleen Jenkins; Editing by G Crosse and Eric Beech)