Recommended Mifepristone Regimen for Medical Abortion
The recommended regimen is mifepristone 200 mg orally followed by misoprostol 800 mcg (administered buccally or vaginally) 24-48 hours later, which is safe and effective through 63 days (9 weeks) of gestation. 1, 2, 3
Medication Administration Protocol
Initial Dose
- Mifepristone 200 mg is taken orally first, which blocks progesterone receptors and causes decidual breakdown of the uterine lining 1
- The medication should be administered as a single oral dose 2
Misoprostol Administration
- Misoprostol 800 mcg is administered 24-48 hours after mifepristone 2, 3
- Route options include:
- Both routes demonstrate similar efficacy, with complete abortion rates of 95-97% 6, 3
Alternative Timing
- Research demonstrates that simultaneous administration (misoprostol given immediately with mifepristone) achieves comparable efficacy (95.1% vs 96.9% complete abortion rate) 4
- However, the 24-48 hour interval remains the standard evidence-based approach 2, 3
Gestational Age Considerations
Efficacy by Gestational Age
- Highest efficacy at 29-42 days gestation (98.8%) 3
- Efficacy remains acceptable through 63 days (95.5%) 3
- The regimen can be safely used up to 63 days (9 weeks) of gestation in outpatient or home settings 6, 3
Important Caveat
- Efficacy decreases slightly with advancing gestational age, with odds of needing aspiration increasing at higher gestational ages 3
- Complete abortion rates remain >95% even at 57-63 days gestation 5, 3
Critical Contraindications and Safety Considerations
Absolute Contraindications
- Previous cesarean delivery is a contraindication to misoprostol due to significant uterine rupture risk 1, 7, 6
- This is a critical safety consideration that must be assessed before prescribing 7
High-Risk Patients
- Patients with end-stage renal disease, heart disease, or other serious conditions should be managed in experienced centers with emergency support services available 1
- Second trimester procedures should be performed where blood transfusion and emergency surgery are available 7
Rh-Negative Patient Management
- RhD testing and Rh immune globulin should be offered to Rh-negative patients when logistically and financially feasible 1
- Administer 50 mcg of Rh immune globulin within 72 hours for first-trimester abortion 1
- 300 mcg may be used if the 50 mcg dose is unavailable 1
Expected Effects and Side Effect Management
Expected Outcomes
- Cramping and bleeding are expected effects, with bleeding lasting an average of 9-16 days 2
- Most women (88-92%) begin bleeding within 4 hours of misoprostol administration 5
Common Side Effects
- Misoprostol causes gastrointestinal symptoms (nausea, diarrhea, vomiting), low-grade fever, and warmth/chills 7, 4, 5
- These can be managed with NSAIDs or antiemetics 2
- Side effects are generally acceptable to 82-91% of patients 5
Rare but Serious Complications
- Ongoing pregnancy, infection, hemorrhage, and undiagnosed ectopic pregnancy are rare complications 2
- Infection requiring hospitalization occurs in 0.01% of cases 3
- Transfusion is required in 0.03% of cases 3
Follow-Up Assessment
- Clinical history combined with serial quantitative beta-hCG levels, urine pregnancy testing, or ultrasonography establishes complete passage of pregnancy tissue 2
- Follow-up evaluation typically occurs 7±1 days after initiating treatment 4
- A second dose of misoprostol may be offered if abortion has not occurred 4, 5