New York Attorney General Letitia James (D) on Monday announced that the state is suing Heartbeat International, an anti-abortion group, for making what she says are misleading and “incredibly dangerous” claims about medication abortion.

The lawsuit also names 11 crisis pregnancy centers across New York as defendants. Prosecutors say the centers are falsely promoting what they call “Abortion Pill Reversal,” an unproven protocol that they claim can reverse a medication abortion.

“Abortions cannot be reversed, and this treatment could be incredibly dangerous,” James said in a statement. “They claim the treatment is safe and effective, but there’s no scientific proof and medical experts warn that it’s unsafe.”

Medication abortion typically requires a two-drug regimen: a dose of mifepristone, which blocks a pregnancy-related hormone called progesterone, followed 24 to 48 hours later by a dose of misoprostol, which causes cramping and empties the uterus.

The lawsuit alleges that Heartbeat International and the other defendants seek to persuade pregnant people to skip the second drug and instead take progesterone to supposedly “reverse” the process.

However, there’s no scientific evidence to support the procedure, according to the American College of Obstetricians and Gynecologists.

An investigation by ACOG concluded that several studies cited by the groups relied on flawed data and highly imprecise methodology.

For instance, a 2020 study intended to evaluate the procedure was halted early due to safety concerns, after three patients experienced “severe hemorrhage requiring ambulance transport.”

California Attorney General Rob Bonta (D) filed a similar lawsuit against Heartbeat International last September. Colorado banned the unproven treatment in April 2023, the first such action in the country, but a federal judge blocked the state from enforcing the ban hours after it was signed.

In a statement, Heartbeat International said it is countersuing James “for egregious violations of fundamental rights, including freedom of speech, free exercise of religion, equal protection under the law, and civil rights violations.”