Women in the U.S. who have trouble accessing an abortion—because of cost, geography, waiting periods, or other reasons—now have another option: the mail. Aid Access, an online organization that allows women to order abortion-inducing medications shipped directly to their home, has been discreetly operating in the United States for the last six months, according to the Atlantic, serving an estimated 600 women so far.

Aid Access isn’t a new idea—it’s a spinoff of Women on Web, a site founded in 2005 by Dutch physician Rebecca Gomperts to supply abortion-inducing drugs to women in countries where abortion is outlawed—but it is new to the U.S., offering a more reliable alternative to shady online sites already selling the drugs. Here’s everything you need to know about the service, also founded by Gomperts, that promises American women access to a safe abortion by mail.

How does it work?

Aid Access supplies the same two drugs you would take for a medication abortion in a U.S. clinic: mifepristone, which was approved by the FDA as an abortifacient in 2000, and misoprostol, which is also used to treat gastric ulcers. By the first half of 2001, 6 percent of abortions performed outside a hospital used the two medications, according to the Guttmacher Institute; by 2014, that figure was up to 31 percent.

When a woman who is at 10 weeks of gestation or less (the drugs are less effective after the 70th day of pregnancy) chooses a medical abortion at a clinic, she’ll take mifepristone—which works by blocking the effects of progesterone, a hormone necessary to maintain a pregnancy, and causing contractions of the uterus—during the clinic visit. She’ll take misoprostol, which causes the uterus to continue contracting, between 24 and 72 hours later.

Things work similarly with Aid Access. After a woman completes an evaluation of her medical history and verifies that she is less than 10 weeks pregnant and lives within one hour of medical help, Gomperts writes a prescription for mifepristone and misoprostol, which is filled and shipped by a pharmacy in India.

Is it safe?

Medication abortion is widely accepted as a low-risk procedure. Research has found that the rate of serious complications requiring hospitalization is less than half of 1 percent when the drugs are taken in the first eight weeks of pregnancy, and FDA clinical trial data shows that failure to end the pregnancy happens in less than 1 percent of cases within 10 weeks. (Nausea, fever, heavy bleeding, and pain are all normal immediately afterward, though you should see a doctor if your symptoms last longer than 24 hours or your pain doesn’t go away with over-the-counter treatments.) In a study of 1,000 women in Ireland who used Women on Web to obtain medical abortions, 95 percent were able to successfully end their pregnancies, 0.7 percent needed a blood transfusion, and 2.6 percent ended up seeking antibiotics.

According to study co-author Abigail Aiken, an assistant professor at the Lyndon B. Johnson School of Public Affairs at the University of Texas, an abortion by mail is more accurately described as a “self-managed abortion.”

“Technically, a ‘back-alley abortion’ would also be a self-managed abortion,” says Aiken. “But now the technology is very different. This is the same medication that’s available in a clinical setting, and that’s been the difference-maker. ‘Back-alley’ tends to connote something unsafe and desperate and dangerous. This is exactly what you’re getting in a clinic; you’re just getting it in the mail.”

A study published earlier this year identified 27 U.S. cities as “abortion deserts,” with the nearest abortion provider more than 100 miles away.

Aiken, whose research has focused on telemedicine and the experience of women in countries with restrictive legislation around abortion, says that whether you need to actually visit a doctor to have a medical abortion is a subject of scholarly debate.

“There’s a line of thinking that the things people get at a clinic might not be entirely necessary,” she says. “A lot of state laws say you need an ultrasound to determine gestation, but studies have shown that women are really good at accurately gauging their own pregnancies.”

Is it legal?

Despite the fact that mifepristone is approved by the FDA, ordering it online is technically breaking the rules. FDA rules stipulate that the drug must be taken in a clinical setting or under a doctor’s supervision and that it can only be dispensed by clinicians who have been pre-approved by the FDA and obtained it from an approved supplier. Since Aid Access provides the medications from a source other than an FDA-approved supplier, it’s not in compliance with the REMS. Earlier this week, the Daily Beast reported that the site is now under FDA investigation.

Someone ordering the medications through Aid Access, “[is] not committing a federal crime, but some states do have laws on the books saying self-managed abortion is a crime,” Aiken says. Three states—Texas, North Dakota, and Ohio—have laws requiring mifepristone be provided in accordance with FDA protocol. In 19 other states, there are laws requiring that the clinician providing the mifepristone be physically present while the patient takes it. So if you’re using Aid Access to have the medications shipped to one of those states, Aiken says, “you could be breaking a law. We’re seeing pregnant people in the United States prosecuted for a lot of reasons; it’s possible that could happen to people who self-manage their abortions.”

What does it cost?

It’s significantly cheaper than a clinic visit. The Guttmacher Institute reported the average out-of-pocket cost for a medical abortion is $483, while the average surgical abortion at 10 weeks is $451. Aid Access charges $95 for the consultation and two medications, and a note on the website says women who can’t afford that fee may be eligible for financial assistance.

Why is this a big deal?

A study published earlier this year identified 27 U.S. cities as “abortion deserts,” with the nearest abortion provider more than 100 miles away. According to the Guttmacher Institute, in 2014 nearly 40 percent of American women between the ages of 15 and 44 lived in a county that had no abortion clinic.

Traveling long distances to obtain an abortion can also have a significant impact on privacy, Aiken says. “Doing that kind of travel in a private way is extremely difficult,” she says, “and that means health care confidentiality is often compromised.”

Assuming it’s not shut down by the FDA, Aid Access could ostensibly help address these issues.

“From a public health standpoint, this kind of access to medication abortion could bring about huge changes,” Aiken continues. “If you look around the U.S., especially in the South, the Midwest, Appalachia—the ‘post-Roe’ world people worry about is already here. They have the right to an abortion; they just don’t have the access. If they can safely access it by telemedicine, that’s a game changer.”