Abortion providers on Wednesday sued Pennsylvania to try to reverse a decades-old state Supreme Court decision that upheld a ban on using state Medicaid funds to cover abortions.

The lawsuit, filed in Commonwealth Court, contends that the ban, which affects low-income women who qualify for the public insurance program, violates equal rights protection provisions in the state constitution.

The ban “deprives low-income women of reproductive health care" and discriminates on the basis of sex, said Susan J. Frietsche, senior attorney with the Women’s Law Project, which filed the suit along with Planned Parenthood Federation of America and others.

Federal law bans the use of federal Medicaid dollars to cover elective abortions, and most states have outlawed the use of state Medicaid funds.

Pennsylvania’s ban, enacted in 1982 and upheld by the state Supreme Court in 1985, allows coverage only if the pregnancy is caused by rape or incest, or the abortion is needed to save the woman’s life.

Frietsche said the litigation was prompted by the evolution of legal thinking and research regarding gender discrimination and abortion access.

In recent years, a state court in Alaska struck down a state law that sought to limit Medicaid abortions. And California researchers have found that women who gave birth after being denied abortions because they were a few weeks over the gestational limit suffered negative emotional, physical, and economic consequences.