OB-GYNs explain how abortion drugs work

Scripps News spoke with two practicing OB-GYNs about how mifepristone and misoprostol work for medication abortion and other health conditions.
Posted at 3:50 PM, Apr 12, 2023

Mifepristone is one of two medications the FDA has approvedto be taken together — one after another — for a medicated abortion. Mifepristone is a one-dose pill only approved for patients up to ten weeks pregnant, or 70 days.

The drug impacts progesterone, a key hormone in menstruation and pregnancy. Progesterone helps the uterus grow during pregnancy and keeps it from contracting. Mifepristone is what the medical community calls a selective progesterone receptor modulator.

"What that means is that it binds to the receptor, the progesterone receptor, a little bit more than the actual progesterone does," obstetrician/gynecologist and complex family planning specialist Dr. Josie Urbina explains. "And therefore, it blocks progesterone from attaching to the receptor."

This prevents the uterus from supporting the pregnancy. Dr. Urbina says mifepristone is "not really" taken on its own, without the second drug in the FDA’s approved regimen.

The second drug in the process is misoprostol. It is usually taken 24 to 72 hours after mifepristone. Misoprostol is also used to get rid of stomach ulcers. For medicated abortions, misoprostol is used to cause contractions and bleeding that empty the uterus. If mifepristone isn’t available, a patient could take multiple doses of misoprostol. But experts warn misoprostol doesn’t work as well alone as the mifepristone and misoprostol combination. It also has side effects, and taking more can make them worse.

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"It's the misoprostol that can make you feel achy, even cause a low-grade fever, cause nausea, and some GI distress," said Dr. Emily Birenbaum, an obstetrician/gynecologist and medical director of women’s health at Caraway Health, a digital health platform that focuses on patients 18-27 years old in California, Colorado, Michigan, New York, North Carolina, and Ohio.

"People who probably wouldn't be good candidates for medication abortion include people who have IUDs in place, someone who's on long-term systemic steroids, someone with chronic adrenal failure, is on blood thinners or has a blood clotting problem, or someone who has very severe anemia," Dr. Urbina said.

According to the Guttmacher Institute, which advocates for abortion rights, 98% of medication abortions in the United States in 2020 used the mifepristone and misoprostol combination. As for safety, a 2022 Scripps News investigation found that for every 1 million patients who used mifepristone, 6 and a half patients died, and that the death rate for penicillin is 4 times higher.

Doctors use mifepristone for things other than medication abortion. The doctors Scripps News spoke with said it’s also used to help a patient pass a miscarriage or induce labor for a stillborn. And research shows it's been used for certain patients with Cushing's syndrome, a disorder in which the body makes too much of the stress hormone cortisol over a long period of time.

It’s also been used for uterine fibroids, which are non-cancerous growths that can be painful. The Mayo Clinic says about 75 to 80% of people with a uterus will have fibroids at some point in their lives.