Medical abortion (medication abortion)

Common medications and how they work

The two medications most widely used today are mifepristone and misoprostol. Mifepristone blocks progesterone, a hormone required to maintain the uterine lining, and is followed after a day or two by misoprostol, a prostaglandin analog that induces contractions and cervical softening. Historically, methotrexate — a drug that interferes with cell division — was also used in combination with prostaglandins, particularly when mifepristone was not available; see methotrexate for historical context. Detailed information on mifepristone can be found at mifepristone.

Procedure, timing and follow-up

Protocols vary by country and provider but typically involve an initial assessment to confirm gestational age and exclude ectopic pregnancy. When used in early pregnancy (commonly up to about ten weeks), the first pill is taken under guidance and the second is taken at home or in clinic. Many programs now permit telemedicine consultations and home administration for eligible people. After the medication course, follow-up is recommended to confirm that the abortion is complete; this is usually done with a follow-up visit, an ultrasound, or a sensitive pregnancy test several weeks later.

Effectiveness, safety and side effects

When used according to current regimens in early pregnancy, medical abortion is highly effective. Typical success rates in the first weeks of gestation are high, although effectiveness declines as gestation advances. The most common effects are cramping and bleeding, which can be heavier than a menstrual period for several hours. Other transient side effects include nausea, fever or diarrhea. Serious complications are uncommon but can include ongoing heavy bleeding, retained tissue requiring surgical evacuation, infection, or an undiagnosed ectopic pregnancy. Overall mortality associated with medication abortion is low compared with the risks of childbirth; for discussion of outcomes see safety statistics.

Contraindications, precautions and when to seek care

• Known or suspected ectopic pregnancy
• Allergy to the medications used
• Certain chronic medical conditions or interactions with other drugs (assessed by a clinician)
• Inability to obtain emergency care if heavy bleeding or other complications occur

People should seek prompt medical attention for very heavy bleeding (soaking through two sanitary pads per hour for more than two hours), severe pain not controlled by analgesics, fever lasting more than 24 hours, or signs of infection.

History, comparisons and access

Medical abortion became widely available in the 1970s and 1980s with evolving drug regimens; the combination of mifepristone and misoprostol emerged as the standard in many places after clinical trials demonstrated high effectiveness and safety. Compared with surgical procedures (such as vacuum aspiration), medication abortion offers a non‑surgical option that some people prefer because it can be completed at home and avoids anesthesia and instrumentation. However, it usually involves a longer period of bleeding and a small chance of incomplete abortion requiring a follow-up procedure. Legal status, availability of specific drugs, and clinical protocols vary between countries and regions, and access has been affected in recent years by telemedicine expansion and regulatory changes in some jurisdictions. For additional resources, see clinical guidance and local providers at medication information and patient resources at medical abortion.