By Kathy Finn

NEW ORLEANS (Reuters) - The Louisiana state House of Representatives on Tuesday evening was set to consider a bill that would ban abortions and launch a battle to overturn the historic Roe v. Wade decision by the U.S. Supreme Court.

The bill by Republican state Rep. John LaBruzzo defines human life as beginning at the moment of conception and makes it a crime to terminate a pregnancy except when the birth would endanger the mother's life.

"Our first intent is to save unborn babies' lives," LaBruzzo told Reuters. "Our second intent is to have an opportunity to mount a challenge that makes it to the Supreme Court."

The measure would repeal previous state exceptions that allowed abortion when a pregnancy results from rape or incest.

Marjorie Esman, executive director of the American Civil Liberties Union of Louisiana, said the bills are "a nationwide movement to erode women's access to health care."

Louisiana joins two other Southern states -- Mississippi and Alabama -- in attempting the most stringent abortion restrictions seen in the nearly four decades since the landmark Supreme Court ruling making abortion legal.

Since the High Court in 1973 upheld a woman's right to seek an abortion in Roe v. Wade, states have passed a wide range of abortion laws aimed at regulating when and under what circumstances a woman may obtain an abortion.

No state has so far succeeded in banning abortion altogether, though many have tightened restrictions on the procedure in recent years.

According to the Guttmacher Institute in Washington, D.C., which conducts research and policy analysis related to reproductive health, 39 states prohibit abortions after a specified point in pregnancy. Many states also impose requirements ranging from minimum waiting periods to state-mandated counseling.

Elizabeth Nash, a public policy associate at the Guttmacher Institute, says about 14 states have this year made some attempt at limiting abortion.

"We have seen the most abortion restrictions adopted in one year that we have ever seen," she said.

Two of the most aggressive efforts are under way in Alabama and Mississippi.

The measures define life as beginning at conception and would ban abortion. The Alabama Senate approved its bill, which is now pending in the House, and Mississippi residents will vote on the issue in November.

Nash says both of those bills "could conceivably" ban many forms of contraception because hormonal methods of contraception such as birth control pills act after fertilization of an egg occurs.

In Louisiana, LaBruzzo maintains that he has no intention of challenging a woman's right to practice contraception.

"This is not about interfering with anyone's ability to receive or participate in birth control," he told Reuters. "What the bill says is that life begins at conception, and a baby who is pre-born should enjoy all the rights that a 1-day-old baby does."

(Editing by Karen Brooks and Greg McCune)