The abortion pill is actually two different medications taken one to two days apart. The first, mifepristone, blocks the hormone that sustains a pregnancy. The second, misoprostol, triggers contractions that expel the pregnancy tissue. Together, they’re about 95% effective through the first nine weeks of pregnancy, and they can be used up to around 11 or 12 weeks with slightly lower success rates.
The Two Medications and What Each Does
Mifepristone is the first pill. Progesterone is the hormone your body produces to maintain a pregnancy. It keeps the uterine lining thick, blood-vessel-rich, and hospitable. Mifepristone binds to the same receptors progesterone uses, essentially locking progesterone out. Without progesterone doing its job, the uterine lining begins to break down. Blood vessels supplying the embryo are damaged, and the attachment between the pregnancy and the uterine wall deteriorates. Mifepristone also starts to promote mild uterine contractions on its own.
Misoprostol is the second pill, taken 24 to 48 hours later. It’s a synthetic prostaglandin, meaning it mimics the natural compounds your body uses to trigger labor contractions. It activates receptors in uterine muscle tissue that cause strong, rhythmic contractions. At the same time, it triggers an inflammatory response in the cervix that softens and opens it. The combination of a softened cervix and powerful contractions moves the pregnancy tissue out of the uterus, similar to what happens during a miscarriage.
How You Take Them
The FDA-approved regimen is one 200 mg mifepristone tablet swallowed with water. Then, 24 to 48 hours later, you take four small misoprostol tablets (800 mcg total) buccally, which means placing two tablets in each cheek pouch, between the gum and cheek. You hold them there for 30 minutes to let them absorb, then swallow any remaining fragments with liquid.
Both steps can be done at home. Some clinics provide the pills in person; others prescribe them through telehealth and mail them to you. Either way, you don’t need to be in a medical facility when you take them.
What It Feels Like
After the first pill, most people feel little or nothing. Some experience mild nausea or light spotting, but the mifepristone is doing its work quietly at the cellular level.
The second pill is when things get intense. Within one to four hours of taking misoprostol, heavy cramping and bleeding begin. This is the medication working: your uterus is contracting to push out the pregnancy tissue. The cramping can be significantly more painful than a normal period. It’s common to pass large blood clots, sometimes up to the size of a lemon, along with clumps of tissue. Most people pass the bulk of the pregnancy tissue within four to five hours, though it can take longer.
Other side effects during this window include low-grade fever, chills, nausea, diarrhea, dizziness, and fatigue. The fever and chills typically resolve within a day. Ibuprofen is the most commonly recommended pain reliever, and taking it about 30 minutes before the misoprostol can help stay ahead of the cramping. A heating pad also helps.
After the heaviest phase passes, lighter bleeding and spotting continue for several weeks. This is normal and tapers off gradually.
Effectiveness by Gestational Age
The two-pill regimen is most effective in earlier pregnancy. Through the first nine weeks, the success rate is around 95% or higher. Between 9 and 12 weeks, large analyses estimate about 94.6% of medication abortions are successful. Beyond 12 weeks, success rates drop further. One study of self-managed medication abortions between 9 and 22 weeks found 89.4% completed with pills alone, meaning roughly one in ten people in that later window needed a procedural follow-up.
When It’s Not Safe to Use
Medication abortion is not an option for ectopic pregnancies, where the embryo implants outside the uterus (usually in a fallopian tube). The pills don’t treat ectopic pregnancy, and taking them could delay diagnosis of a condition that can become life-threatening. An ultrasound or clinical evaluation confirms the pregnancy is in the uterus before pills are prescribed.
If you have an IUD in place when you become pregnant, it needs to be removed before starting the medication. Pregnancy with an IUD carries a higher risk of ectopic pregnancy, so that possibility has to be ruled out first. The IUD also poses a theoretical risk of uterine perforation during the strong contractions misoprostol causes.
Other situations that make the abortion pill unsafe or require special consideration include severe uncontrolled asthma treated with long-term corticosteroids (because mifepristone can interfere with how the body manages cortisol), adrenal insufficiency, severe anemia, bleeding disorders, a previous allergic reaction to either medication, and a rare metabolic condition called porphyria.
Warning Signs to Watch For
Heavy bleeding is expected, but there’s a threshold that signals a problem. Soaking through more than two full-size pads per hour for two consecutive hours is concerning and may indicate the abortion is incomplete or that tissue remains in the uterus. A fever lasting more than 24 hours, or a fever that starts days after taking the pills rather than immediately after, also warrants medical attention.
Confirming It Worked
About two weeks after the abortion, you’ll take a low-sensitivity pregnancy test. Regular pregnancy tests are too sensitive for this purpose: pregnancy hormone levels drop slowly, and a standard test could still read positive even after a successful abortion. The special low-sensitivity test your provider gives you is designed to detect only the higher hormone levels that would indicate an ongoing pregnancy. If the test is negative, the abortion is complete.
If it’s positive, or if you never experienced significant bleeding and cramping after taking the misoprostol, a follow-up visit determines whether you need a second dose of misoprostol or a brief procedural abortion to complete the process.
Effects on Future Fertility
A medication abortion does not raise the risk of fertility problems or complications in future pregnancies. Ovulation can return as soon as two weeks after the abortion, which means pregnancy is possible again almost immediately. If you don’t want to become pregnant right away, contraception can be started as soon as the day after you take the misoprostol, or at your follow-up visit.