Medical Abortion with Mifepristone and Misoprostol
For early pregnancy termination up to 63 days (9 weeks) gestation, the combination of mifepristone 200 mg orally followed by misoprostol 800 mcg (buccal or vaginal) 24-48 hours later is highly effective with a 92-98% complete abortion rate and can be safely administered in outpatient or home settings. 1, 2, 3
Regimen and Administration
Standard Protocol:
- Mifepristone 200 mg orally as the initial dose 2, 3
- Misoprostol 800 mcg administered 24-48 hours later, either buccally or vaginally 2, 3, 4
- The 800 mcg dose is more effective than 400 mcg 3
- Both buccal and vaginal routes are equally effective, though sublingual administration causes more gastrointestinal side effects (nausea, vomiting, diarrhea) and fever 4
Gestational Age Limits:
- Medical abortion is approved up to 77 days (11 weeks) gestation 2
- Before 9 weeks, outpatient or home-based care is appropriate 1
- First trimester is the safest time for any pregnancy termination 5
Mechanism and Effectiveness
How It Works:
- Mifepristone blocks progesterone receptors, causing decidual breakdown and cervical softening 6
- Misoprostol induces uterine contractions to expel pregnancy tissue 2
Success Rates:
- Complete abortion: 92-98% with the combination regimen 2, 3, 4
- Ongoing pregnancy: 1-3% 3, 7
- Incomplete abortion requiring surgical intervention: 3-5% 7
- Combination therapy is significantly more effective than misoprostol alone 3
Expected Effects and Side Effects
Normal Expected Effects:
- Cramping and bleeding are expected therapeutic effects 2
- Bleeding lasts an average of 9-16 days (median 17 days) 2, 4
- Heavier bleeding than normal menses is typical 2
Common Side Effects:
- Gastrointestinal symptoms: nausea, vomiting, diarrhea (24% vomiting rate, 7% diarrhea) 4, 8
- Low-grade fever and chills (more common with sublingual route) 2, 4
- Abdominal pain (62% require no analgesia) 8
- Managed with NSAIDs or antiemetics 2
Critical Safety Considerations
Absolute Contraindications:
- Ectopic pregnancy must be ruled out before administration 2
- Confirmed intrauterine pregnancy location required via ultrasound if dating uncertain or risk factors present 2
- Do NOT use misoprostol in third trimester for women with prior cesarean section (13% uterine rupture risk) 5, 9
Important Warnings:
- Mifepristone will terminate pregnancy—pregnancy must be excluded before use 6
- Non-hormonal contraception required during and for one month after treatment 6
Pre-Treatment Requirements
Gestational Age Confirmation:
- Use ultrasound or reliable menstrual history 2
- Ultrasound mandatory when clinical dating uncertain or ectopic pregnancy risk factors present 2
Rh Status:
- All Rh-negative women must receive anti-D immunoglobulin within 72 hours 9
- Dose: 50 mcg preferred (or 300 mcg if smaller dose unavailable) 9
Follow-Up and Confirmation of Complete Abortion
Assessment Methods:
- Clinical history combined with one of the following 2:
- Serial quantitative β-hCG levels (should decline appropriately)
- Urine pregnancy testing (should become negative)
- Ultrasound examination
Timing:
- Follow-up typically 7-14 days after misoprostol administration 2
Rare but Serious Complications
Complications to Monitor:
- Ongoing pregnancy: 1-3% (requires surgical completion) 3, 7
- Hemorrhage requiring transfusion, hospitalization, or surgery: rare 7
- Infection/endometritis: rare 2, 7
- Undiagnosed ectopic pregnancy: rare but potentially life-threatening 2
Comparison with Surgical Abortion
Medical Abortion Advantages:
- Avoids anesthesia risks 9
- Avoids surgical complications (uterine perforation, cervical trauma, Asherman's syndrome) 9
- Can be performed at home or outpatient setting 1, 2
- Less invasive 8
Surgical Abortion Advantages:
- Lower hemorrhage risk (9.1% vs 28.3% medical) 1
- Lower infection risk (1.3% vs 23.9% medical) 1
- Lower retained tissue rate (1.3% vs 17.4% medical) 1
- Single visit completion 1
Critical Pitfall: Medical abortion may be more psychologically traumatic for some patients compared to surgical options—patient preference matters 1
Special Populations
High-Risk Cardiac Patients:
- Should be managed in experienced centers with cardiac surgery availability 5
- Hospital setting preferred over outpatient for complex heart disease 5
- Prostaglandin E compounds can lower systemic vascular resistance and blood pressure 5
End-Stage Renal Disease:
- Mifepristone can be used up to 7 weeks gestation 10
- Must be administered in hospital setting with close monitoring 10
- Increased bleeding risk due to uremic platelet dysfunction 10
- Higher infection risk due to immunocompromised state 10
Post-Abortion Contraception
Immediate Initiation: