Louisiana women seeking an abortion would have to drive to Illinois or New Mexico for the pregnancy-ending procedure should the U.S. Supreme Court uphold the constitutionality of a Mississippi law and overturn Roe v. Wade.

The nine justices will hear arguments Wednesday morning in a case that both sides say is the most important challenge to the landmark Roe decision in 48 years. Roe affirmed that a pregnant woman’s right to an abortion was protected by the equal protection and privacy clauses articulated in the 14th Amendment of the U.S. Constitution.

The decision won’t be rendered until June, and a majority could go in any direction. But for the first time, the Supreme Court is reviewing the standard it set in 1973 and reinforced in subsequent cases: States are forbidden from placing an “undue burden” on women seeking to terminate a pregnancy during the 24 weeks before the fetus can live on its own outside the mother’s womb.

The 2018 Mississippi law would ban abortions after 15 weeks of pregnancy, well before viability.

Louisiana voters approved a constitutional amendment last year and a trigger law banning abortions should the high court overturn Roe. The three abortion clinics — in Baton Rouge, New Orleans and Shreveport — would close.

Louisiana is among the dozen states, mostly in the South and Midwest, that have enacted laws that would ban all or nearly all abortions if Roe were overturned, according to the Guttmacher Institute, a Washington, D.C.-based organization. All the states sharing borders with Louisiana would forbid abortions and most of the neighbors' neighbors have passed similar laws too.

Fifteen states, mostly in the north and west, and Washington, D.C., have enacted laws that would protect abortions should Roe be overturned. Maryland and Illinois are the closest to Louisiana.

Even if the justices upheld Mississippi’s law without explicitly overruling Roe, Louisiana also has a 15-week ban on the books that would take immediate effect.

Arguments will focus on the question of whether “all pre-viability prohibitions on elective abortions are unconstitutional.”

Viability is a scientific determination, and anti-abortion advocates argue that science shouldn’t be the criteria, said Benjamin Clapper, executive director of Louisiana Right to Life. “That’s going to change over time, and a person’s right to life shouldn’t be determined by that,” he added.

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Clapper’s group and its allies are holding news conferences in New Orleans, Baton Rouge and Shreveport on Wednesday to remind people of the arguments before the Supreme Court in Washington, D.C., and to launch a campaign called “Louisiana Is Ready for a Post-Roe, Abortion-Free Future,” with advertising in eight newspapers and on 70 digital billboards statewide. The campaign will publicize the services and resources available for pregnant women and their families.

Louisiana has an abundance of public social services in place, Clapper said, that help mothers with prenatal care, with the cost of the birth, nutrition, job placement and day care assistance. “Those are in place no matter what happens to Roe v. Wade and will be in place when abortions are not available,” he said.

Advocates for abortion accessibility argue that low-income women already have trouble accessing essential health services, particularly during pregnancy. “Black women were nearly two and a half times more likely to die from childbirth than were white women,” according to a brief filed with the Supreme Court by the National Birth Equity Collaborative. African American women accounted for 65% of abortions performed in Louisiana in 2020, according to state health statistics.

“We need to improve birth equity, to address health disparities, and to make sure that we can all plan our families and our futures with dignity. That includes making sure that abortion is not only legal, but also accessible, affordable, and supported in our communities,” Jessica Frankel, coordinator at Louisiana Coalition for Reproductive Freedom, said in a prepared statement.

Her organization and other groups that support abortion rights are holding rallies Wednesday on the Supreme Court steps and in Jackson, Mississippi.

The number of abortions in Louisiana have been decreasing over the past decade.

There were 7,448 abortions in Louisiana in 2020, according to preliminary figures by the Louisiana Department of Health. About 58% of the abortions in 2020 were on women between the ages of 20 and 29. Unmarried women account for 89% of the procedures performed in Louisiana last year.

Shreveport’s Hope Medical Group for Women remains the state’s largest provider of abortions. Administrator Kathaleen Pittman said the clinic had “definitely seen an increase in Texas residents” since the Lone Star State’s Republican legislative majority passed and the GOP governor signed a law that forbids abortions after detection of a fetal heartbeat.

The law also circumvents federal courts by allowing everyday citizens to sue the mother, the physician and anyone else connected to the procedure. The U.S. Supreme Court twice refused to suspend the law until its constitutionality is decided.

Pittman added in an email that patients “are having to schedule weeks out at this point due to volume.”

Email Mark Ballard at mballard@theadvocate.com.