The US Supreme Court is hearing arguments about the constitutional validity of a Mississippi law that bans abortions after 15 weeks, and threatens the right to end pregnancy for tens of millions of women in another 21 states. The Supreme Court’s landmark ruling in a case known as Roe v Wade in 1973 ensured for women in the United States an absolute right to an abortion in the first three months of pregnancy, and limited rights in the second three months.

In 1992, the Supreme Court upheld and revised those rights when it ruled that states could not place an “undue burden”, defined as a “substantial obstacle in the path of a woman seeking an abortion before the fetus attains viability”, in the Planned Parenthood v Casey case.

As legal uncertainty grows, more turn to abortion pills by mail

How does the Mississippi law threaten Roe v Wade?

The Gestational Age Act, a state law passed in Mississippi in 2018, deems abortions illegal after the first 15 weeks of pregnancy, including those caused by rape or incest. It provides exceptions for medical emergencies or severe fetal abnormality.

The Supreme Court has never allowed states to ban abortion before the threshold of roughly 24 weeks when a fetus can survive outside the womb.

The Gestational Age Act has been blocked by lower courts and faces a legal challenge in the Supreme Court from Jackson Women’s Health Organization, the only state-licensed abortion clinic in Mississippi.

As legal uncertainty grows, more turn to abortion pills by mail

Mississippi is arguing for for Roe v Wade to be overturned, and with it the constitutional right to an abortion in the US, paving the way for 21 other states to introduce their own bans, some probably more severe than Mississippi’s.

In a legal brief filed this summer Mississippi Attorney General Lynn Fitch – who will be defending the state’s law – said that throwing out Roe would effectively return decision-making about abortion to the American people and their elected officials.

“The matter should be returned to the States and the people,” she wrote.

Overall, some 36 million US women of reproductive age (18-49) could lose access to abortion, according to healthcare organisation Planned Parenthood.

In 15 states and the District of Columbia, state law guarantees the right to an abortion even if Roe v Wade is overturned.