The U.S. Conference of Catholic Bishops are being sued by the American Civil Liberties Union (ACLU) for teaching Catholic hospitals not to perform direct abortions.

The ACLU filed a federal lawsuit against the bishops on behalf of a Michigan woman named Tamesha Means, the Catholic News Agency reports.

Means was treated at Mercy Health Muskegon, a Catholic hospital in Michigan, in 2010 when she was 18 weeks pregnant and her water broke.

The ACLU claims that hospital was negligent because it did not tell Means that an abortion was “an option” and allegedly “the safest course for her condition.”

The legal group said the woman was in “excruciating pain” and the pregnancy posed “significant risks to her health.” She also suffered “extreme distress” and an infection that can cause infertility, the organisation said.

The ACLU lawsuit, filed in U.S. District Court in Michigan, claims that because the U.S. bishops’ conference approved the ethical directives governing Catholic hospitals, the conference is “ultimately responsible” for the “unnecessary trauma and harm” that Means and other pregnant women allegedly experienced at these hospitals.

The U.S. bishops’ ethical and religious directives for Catholic health care services, most recently updated in 2009, seek to affirm the life of all parties involved in a medical situation. They allow operations, treatments and medications for a pregnant woman to treat a “proportionately serious pathological condition” if these procedures and treatments cannot be postponed, “even if they will result in the death of the unborn child.”

However, Catholic ethics bar the direct and intentional killing of an unborn baby through abortion.

The American Civil Liberties Union has long backed legal sanctions against Catholic institutions that refuse to recognize what it considers “reproductive rights.” It has called for federal investigations of Catholic hospitals that refuse to perform abortions. It has also advocated restrictions on the ability of Catholic hospitals and other institutions to refuse to perform procedures they find objectionable, including sterilisations or abortions.

The ACLU is also a vocal defender of the federal HHS mandate that requires many employers to provide health insurance plans covering sterilisation and contraception, including drugs that may cause early abortions, in their employee health plans.

A legal expert has said that the lawsuit ignores religious freedom protections and laws.

“The ACLU’s idea that the courts should hold religious institutions liable for their religious teachings on abortion makes no sense,” Professor Mark Rienzi of the Catholic University of America’s Columbus School of Law said.

He emphasised that the U.S. Constitution “unequivocally protects the right of religious leaders to teach that abortion is wrong.”

“The Catholic Church holds the view that a doctor treating a pregnant woman has two patients to care for, and most pregnant women probably agree with that view,” Professor Rienzi said.

“The ACLU is allowed to disagree, but it should not be allowed to force that view on all healthcare providers.”

Professor Rienzi, who teaches constitutional law and religious liberty law, was critical of the lawsuit.

“It is no surprise that the ACLU thinks abortion is good medicine,” he said. “But federal and state law protect the right of religious providers to think otherwise, and to refrain from providing or referring for abortions.”

The ACLU’s contention that an abortion was medically necessary to help Means has also been rejected.

“Abortion is never necessary to save the life of the mother,” said Dr. Brian C. Calhoun, a professor and vice-chair in the obstetrics and gynecology department at West Virginia University-Charleston.