An expansive study released Monday in the journal Contraception found that evidence-based alternatives to the Food and Drug Administration-approved regimen for medication abortion are safe and effective.

The distinction between “evidence-based” and “FDA-approved” matters a great deal for women in early pregnancy who want to use the drugs mifepristone and misoprostol to induce a miscarriage. The FDA protocol requires a higher dose of medication and more doctor’s visits—both of which make the process more expensive and harder to access—and has an earlier cut-off date in pregnancy for using the protocol.

The distinction also matters because many anti-choice laws try to restrict women’s access to medication abortion by forcing doctors to use the FDA protocols. The new study adds to a robust body of evidence that these restrictive laws have no scientific basis.

The study, which spanned five years and followed 13,000 women who used evidence-based protocols for medication abortion at Los Angeles-area Planned Parenthood clinics, found that the protocols were more than 98 percent effective for pregnancies of up to 42 days’ gestation, and more than 95 percent effective up to 63 days.

The FDA protocols only recommend using medication abortion up until 49 days of gestation, or about seven weeks, and are less than 85 percent effective after 49 days.

Doctors and experts say the FDA protocol—which is based on a regimen developed in France 25 years ago and used 15 years ago in clinical trials to approve the drug in the United States—is outdated and out of step with best medical practice.

“Off-label” prescription of drugs is both common and necessary in medicine. The FDA approval process for a drug is long and cumbersome, while evidence on the safe uses of a given drug may evolve much more quickly. As a result, drug manufacturers don’t often go through the expense and hassle of petitioning the FDA to update its guidelines on every drug on the market because it is accepted that clinicians can and routinely do rely on evidence-based protocols that evolve in the years after initial drug approval as new and better evidence emerges from the field.

“The way a medication is administered often evolves after the FDA has first approved it for use based on new medical research and professional experience,” Kelly Cleland, one of the study’s authors, said in a statement.

This is how aspirin came to be used to prevent heart attacks, Cleland noted.

The FDA explicitly allows doctors to use off-label drugs, cautioning only that they base the use “on firm scientific rationale and on sound medical evidence.”

There have been a number of other anti-choice efforts to to try to force doctors to practice outdated medicine. For instance, 16 states restrict the use of telemedicine for medication abortion, which has also been shown to be safe and helps patients in rural areas who live far from a clinic.

In just the past two months, legislatures in South Carolina, Arkansas, Florida, and Iowa have introduced measures to restrict or ban medication abortion.