(Reuters) -Five women who said they were denied abortions despite grave risk to their lives have sued the state of Texas, in the first apparent case of pregnant women suing over curbs imposed after the U.S. Supreme Court overturned Roe v. Wade last June.

The lawsuit filed on Monday asks a state court in Austin, the state's capital, to clarify that doctors cannot be prosecuted for providing abortions, if in their good faith judgment the procedure is necessary to treat emergencies that threaten patients' life or health.

Like most of the 13 U.S. states with near-total abortion bans, Texas allows exceptions when a doctor finds a medical emergency.

But the lawsuit, backed by the abortion rights group Center for Reproductive Rights, says Texas' law is unclear, leading doctors to refuse to perform abortions even when exceptions should apply, for fear of losing their licenses and facing up to 99 years in prison.

Texas banned most abortions shortly after the Supreme Court overturned Roe, its landmark 1973 decision guaranteeing abortion rights nationwide.

A spokesperson for Texas Attorney General Ken Paxton, a Republican, said in an email that he will "continue to defend and enforce the laws duly enacted by the Texas legislature."

The spokesperson pointed to Paxton's guidance last July that the Texas law "protects women facing life-threatening physical conditions resulting from pregnancy complications."

One of the plaintiffs in Monday's lawsuit, Amanda Zurawski, said she was hospitalized in Texas with a premature rupture of membranes, meaning her fetus could not be saved, but was told she could not have an abortion until fetal cardiac activity stopped or her condition became life-threatening.

Zurawski said she developed sepsis within days, which required intensive care and allowed the hospital to induce labor.

The other four women said they had to travel out of state to obtain abortions, to avoid serious medical complications.

All five stood on Tuesday under a cloudy sky in front of Texas' state capitol to share their stories with reporters.

"I cannot adequately put into words the trauma and despair that come with waiting to either lose your own life, your child’s life, or both," Zurawski said.

(Reporting by Jonathan Stempel and Brendan Pierson in New York, and Gabriella Borter in Washington, Editing by Mark Porter and Alexia Garamfalvi)