(CNN) A European organization that provides doctor-prescribed abortion pills by mail is under order by the US Food and Drug Administration to stop deliveries.

The federal agency sent a warning letter to Aid Access this month requesting that it "immediately cease causing the introduction of these violative drugs into U.S. Commerce."

"The sale of misbranded and unapproved new drugs poses an inherent risk to consumers who purchase those products," the letter says. "Drugs that have circumvented regulatory safeguards may be contaminated; counterfeit, contain varying amounts of active ingredients, or contain different ingredients altogether."

Dr. Rebecca Gomperts, founder of Aid Access, did not respond to a request for comment on the new letter. But last fall, soon after her work went public, she said that safety concerns about Aid Access and the medications it prescribes were "totally unfounded." She insisted that everything she does "is according to the law" and that the FDA's restrictive handling of abortion medication is "based on politics, not science."

For more than 12 years, Gomperts' site Women on Web has been offering a similar service to women in countries where abortion is illegal. She says she quietly began offering services in the United States, under the name Aid Access, after receiving about 1,000 emails from people requesting help.

"I realized it was time," she said. "Something had to be done."

Meeting a growing demand

Aid Access says it uses telemedicine, including online consultations, to offer services to healthy women who are less than nine weeks pregnant. If a woman completes the consultation and is deemed eligible for medical abortion, Gomperts writes a prescription for the two pills used to terminate the pregnancy. Prescriptions are sent to a pharmacy in India, which fills and mails orders to the United States.

The protocol combines two drugs. Mifepristone blocks progesterone, a hormone that allows the pregnancy to continue. Misoprostol stimulates the uterus, causing it to cramp, bleed and contract -- ending the pregnancy in what is essentially a miscarriage, Aid Access explains on its website.

A 2015 study showed the regimen to be about 97% effective. And interest in self-managing or self-inducing abortions is on the rise, according to various reports.

In a one-month period in 2017, research published last year showed that there were nearly 210,000 US Google searches for information about self-abortion. This indicates a demand for alternatives, perhaps driven by barriers to clinic access due to financial hardship, geographic distance, fear of being publicly shamed or other reasons.

And while the overall number of abortions has gone down, medical abortions grew from 6% of nonhospital abortions in 2001 to 31% in 2014 in the United States, according to the Guttmacher Institute , a reproductive rights think tank. In 2014, 45% of abortions before nine weeks of gestation were induced by medication.

Anticipating 'horror stories'

Criticism of Aid Access came quickly last fall, as soon as anti-abortion groups learned of the organization's efforts.

"Handing out deadly drugs through the mail is a disaster waiting to happen," Kristan Hawkins, president of Students for Life of America, said in a statement . "Risking women's lives to make a political point and a quick profit makes no sense, and we sadly anticipate horror stories when inevitably something goes wrong."

But Gomperts was unfazed, saying that those who fixate on the risks of medical abortion "don't believe in science" and that the procedure she follows is "very safe."

"Less than one in every 100,000 women who use a medical abortion die, making medical abortions safer than childbirth and about as safe as naturally occurring miscarriages," she posted on her site.

In the group's guidelines for managing first trimester abortions , it says, "Medical abortion can be provided safely and effectively via telemedicine with a high level of patient satisfaction; moreover, the model appears to improve access to early abortion in areas that lack a physician health care provider."

Awaiting a response

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There are other ways to get abortion pills by mail in the United States, for women who can't get to or afford clinic visits, but Aid Access is the most affordable option at $95. It also offers the possibility of financial help, according to its website. Plus, Aid Access is the only company to offer physician oversight, according to a report card issued by the grassroots group Plan C , which aims to educate women about self-managed abortion. Aid Access was the only one of nine suppliers to receive an A.

Aid Access has 15 business days from receipt of the FDA warning letter, which was dated March 8, to respond. The organization is asked to describe what it will do to remedy any violations, explain why it needs more time to make corrections or offer reasoning for why it is not in violation of regulatory safeguards.