From the Guidelines
Therapeutic abortion medications should involve a two-drug regimen of mifepristone followed by misoprostol, with the standard protocol beginning with 200mg of mifepristone taken orally, followed 24-48 hours later by misoprostol, usually 800mcg administered buccally or vaginally, as this regimen is approximately 95-98% effective for pregnancies up to 10 weeks 1.
Key Considerations
- The first trimester is the safest time for elective pregnancy termination, which should be performed in a hospital setting to ensure availability of emergency support services 1.
- Mifepristone blocks progesterone receptors and destabilizes the pregnancy, while misoprostol causes uterine contractions to expel the tissue.
- Patients should expect cramping and bleeding, typically heavier than a normal period, starting within hours of misoprostol administration, and pain management with ibuprofen (600-800mg every 6 hours) and possibly acetaminophen is recommended.
Important Details
- Follow-up is crucial to confirm complete abortion, either through ultrasound or serial hCG measurements.
- Side effects may include nausea, vomiting, diarrhea, fever, and chills.
- For pregnancies beyond 10 weeks, different dosing or surgical options may be more appropriate.
Recent Guidelines
- The most recent study 1 from 2024 does not provide new information on therapeutic abortion medications, but rather discusses mifepristone as a potential treatment for central serous chorioretinopathy.
- Other studies 1 provide additional information on mifepristone and its uses, but do not change the recommended protocol for therapeutic abortion medications.
From the FDA Drug Label
Mifepristone can cause termination of pregnancy. Mifepristone is contraindicated in pregnant patients. Women who can become pregnant must: have a negative pregnancy test before starting mifepristone, have a negative pregnancy test before restarting mifepristone if you stop taking it for more than 14 days, use a non-hormonal form of birth control while taking mifepristone and for 1 month after stopping mifepristone.
Mifepristone is used for therapeutic abortion. The medication will cause termination of pregnancy and is contraindicated in pregnant patients. To prevent pregnancy, females of reproductive potential must use a non-hormonal form of birth control while taking mifepristone and for 1 month after stopping the medication 2.
From the Research
Therapeutic Abortion Medications
- Therapeutic abortion medications include mifepristone and misoprostol, which are used in combination or alone for medication abortion 3, 4, 5, 6, 7.
- The combination of mifepristone and misoprostol is highly effective for early abortion, with success rates ranging from 92% to 97% at ≤49 days' gestation 5, 7.
- Misoprostol-only regimens are also effective, with an updated regimen of 800 μg of misoprostol administered buccally, sublingually, or vaginally every 3 hours for three or more doses being highly effective for medication abortion 3.
- The use of mifepristone 200 mg 1 to 2 days before misoprostol 400 mcg vaginally every 3 hours is supported for second-trimester medical abortion at ≥12 weeks' gestation 4.
- Vaginal misoprostol appears to be most efficacious with fewest side effects, but sublingual and buccal routes are also acceptable 4.
Efficacy and Safety
- Mifepristone in combination with misoprostol is effective in 92-95% of women for early pregnancy termination 7.
- Incomplete abortion requiring surgical abortion after the fact occurs in 3-5% of women, and pregnancy continues 1-2% of the time 7.
- Adverse effects of mifepristone and misoprostol include abdominal pain, and less commonly, serious adverse effects such as incomplete abortion, endometritis, and bleeding warranting transfusion, hospitalization, or surgery 7.
Administration and Regimens
- Mifepristone and misoprostol can be administered in different regimens, including mifepristone 600 mg followed by 400 microg misoprostol orally, or mifepristone 200 mg followed by misoprostol 400 mcg vaginally every 3 hours 4, 5.
- The use of a lower mifepristone dose of 200 mg and in-home self-administration of misoprostol appears safe and effective 5.
- Vaginal rather than oral administration of misoprostol may have advantages, including improvement in the efficacy of mifepristone regimens at >49 days' gestation 5.