Eliminating the federal right to abortion surprisingly hasn't reversed a yearslong rise in the number of legal abortions in the U.S. — but a case the Supreme Court hears on Tuesday just might.

Why it matters: The justices will consider rolling back federal policies that made it easier to access a key abortion drug that's grown in prominence as states enacted near or total abortion bans after Roe v. Wade was overturned in 2022.

The big picture: The number of abortions had steadily dropped since the early 1990s before ticking up starting in 2019 and surpassing 1 million last year for the first time in over a decade, according to the Guttmacher Institute, an abortion rights think tank.

• Women's health experts who expected a rapid drop-off in abortion numbers post-Roe said it's not entirely clear why they've continued to rise, but expanded access to the abortion drug mifepristone is seen as a major factor.
• There's been a "kind of a paradoxical effect," said Alina Salganicoff, director of women's health policy at KFF.

Zoom in: The Food and Drug Administration's loosened restrictions on abortion pill mifepristone, which is part of a two-drug regimen, in recent years have allowed patients to take it later in pregnancy, expanded who could prescribe it, and also allowed for it to be prescribed online and mailed directly to patients.

• The telehealth policy, which the FDA temporarily implemented during the COVID-19 pandemic before making it permanent, is really "what opened the gate" to the drug's broader use, Salganicoff said.
• Medication abortion accounted for 63% of abortions last year, up from 53% in 2020, per Guttmacher.

Anti-abortion advocates and doctors who brought the Supreme Court case argue FDA policies since 2016 that loosened restrictions should be revoked because the agency didn't properly account for safety concerns.

• Many studies have found that mifepristone is safe and effective, and mainstream medical organizations support its use.
• Rolling back the FDA policies "would result in increased delays in care for most patients and a complete loss of access to mifepristone for many others," the American College of Obstetricians and Gynecologists argues.

Between the lines: Other factors that may explain rising abortion numbers are growing financial assistance and supportive policies in states that favor access to the procedure.

• While abortion has dropped sharply in states with strict bans, that's been offset by "monumental efforts on the part of clinics, abortion funds and logistical support organizations" to help people access the procedure where it's legal, Guttmacher said.
• States bordering those with abortion bans have seen the largest increases since 2020, likely due to people traveling for the procedure. But even those that don't border states with bans saw a 17% increase between 2020 and 2023.

There's also possibly less stigma around abortion as people talk more openly about it, Salganicoff suggested.

• "We don't have data to back that up, but we also do see in the polling data an increase in support for abortion access," Salganicoff said.

Less understood is whether the increase is due to fewer people wanting children or if more people want to delay having kids.

• Broader takeup of more effective contraception is understood to have been a major factor in the declining number of abortions before their recent rise.
• There's also concern that a surge in online misinformation about contraception that's geared at younger people is fueling an increase in unwanted pregnancies.

The bottom line: The recent increase in U.S. abortions has likely been enabled by less stringent FDA restrictions on mifepristone.

• But if the Supreme Court reverses the agency's moves, that could have the effect that its 2022 ruling didn't — a drop in the number of U.S. abortions.