Houston, Jan 18 (IANS): The Fifth US Circuit Court of Appeals has sent a legal challenge filed by abortion clinics against Texas' highly controversial law banning abortion to the state's Republican-majority Supreme Court, a move widely seen as the latest setback for abortion providers.

The decision may significantly delay the case and keep the Republican-backed near-all abortion ban in effect since it could take months before the challenge returns to a federal court, or never, Xinhua news agency quoted local analysts as saying.

"This decision now keeps the case in limbo -- and abortion after six weeks in the nation's second-largest state -- a dead-letter, indefinitely," Steve Vladeck, a University of Texas School of Law professor, tweeted.

Until a decision is made, Texas abortion providers have mostly stopped performing the procedure, even though Supreme Court decisions have established a constitutional right to abortion after the landmark Roe v. Wade decision that firstly made abortion legal nationwide in 1973.

The US Supreme Court has largely declined to intervene in the Texas case three times, most recently in December when justices kept the ban in effect while allowing a legal challenge to move through a lower state court.

Taking effect from September 1 as reportedly the most restrictive abortion ban in the country, the Texas law prohibits abortions once cardiac activity is detected in an embryo, which can happen as early as about six weeks before many women are aware of their pregnancy.

The state law makes no exceptions for pregnancies resulting from incest or rape.

Furthermore, it allows most US citizens, no matter where they live, to file lawsuits against abortion providers who they think infringed the rule.