Those restrictions have forced clinics across the country to close their doors, curbing access to facility-based procedures, especially for lower-income women. Even where women have access to providers, they often face multiple barriers to care, including weekslong waits for an appointment, crowds of protesters at clinics and a price up to $600.

Since 2011, when the first of those restrictions were enacted, researchers have documented a sharp increase in the number of Google searches for self-induced abortion. Alarmed by the trends, some have warned of a return to the era before Roe v. Wade, when women were forced to risk their lives with coat hangers. And indeed, in September 2015, a woman in Tennessee was charged with attempted murder for using a hanger to try to abort her 24-week-old fetus.

The reality, however, is that increasingly, self-induced abortion in the United States means using pills procured through the mail, much as it is in many other countries. Women on Web, a Netherlands-based nonprofit collective that pioneered the practice of putting the pills directly into women’s hands, has provided abortion medications to more than 50,000 women in 130 countries. While Women on Web focuses on serving women in countries where abortion is legally restricted, Safe2Choose, a social enterprise formed in 2015, sends nearly half of its shipments to countries where abortion has long been legal and widely available.

“It’s the convenience and the privacy,” said a Safe2Choose executive who requested anonymity because of the sensitivity of the issue. “You don’t have to pay hundreds of dollars.” Though the groups do not mail pills to the United States — neither organization is willing to risk a legal backlash that could harm operations elsewhere — the Safe2Choose website receives tens of thousands of monthly visitors from the United States alone, the executive said. “First they watch the video, then they read the testimonials. They seem to want to understand how it works and to assess whether we’re reliable.”

“The fact is, women in the U.S. are already doing this, and the reproductive health community needs to catch up,” Ms. Wells said. “We started Plan C because we believe it’s time for bold action. We have to make sure women have the information they need, that they know their rights” — for example, that they are not obligated to report to the police or providers that they have taken abortion pills; that the drugs can’t be detected in their blood; and that knowing that a woman has used the pills has no bearing on follow-up care, which is the same as for a natural miscarriage.

The risks of self-induced abortion today are primarily legal. “We’ve discovered 40 different kinds of laws that are potentially implicated when someone ends their own pregnancy,” said Jill E. Adams, chief strategist of the Self-Induced Abortion Legal Team, a nonprofit consortium formed in 2015 to support advocates who legally share information on self-induced abortion and to halt its criminalization. So far, she said, the S.I.A. team has identified 18 arrests related to self-induced abortion around the country, “but I’m afraid that’s just what made the news. I suspect the true number is significantly higher.”