Guidelines for Using RU486 (Mifepristone) for Medical Abortion
Mifepristone (RU486) is most effective for medical abortion when used in combination with misoprostol, with a success rate of 95-98%, compared to only 31% when used alone. 1
Medication Regimen
Dosing and Administration
- Standard dose: 200 mg mifepristone orally, followed by 800 mcg misoprostol 2, 3
- Misoprostol administration:
Gestational Age Limitations
- FDA-approved regimen: Up to 70 days (10 weeks) gestation
- Evidence supports effectiveness at:
Pre-Procedure Assessment
Required Testing
- Confirm intrauterine pregnancy and gestational age
- Methods:
- Ultrasound (preferred when dating cannot be confirmed clinically)
- Menstrual history (when reliable) 2
- Quantitative β-hCG levels (as needed)
- Screen for contraindications
Contraindications
- Confirmed or suspected ectopic pregnancy
- IUD in place (must be removed first)
- Chronic adrenal failure
- Concurrent long-term corticosteroid therapy
- History of allergy to mifepristone or misoprostol
- Hemorrhagic disorders or anticoagulant therapy
- Severe anemia
Procedure Protocol
Day 1: Mifepristone Administration
- Administer 200 mg mifepristone orally
- Provide patient education on:
- Expected effects (cramping, bleeding)
- Warning signs requiring immediate medical attention
- Follow-up instructions
Day 2-3: Misoprostol Administration
- 800 mcg misoprostol buccally or vaginally, 24-48 hours after mifepristone
- For gestations beyond 63 days, consider two doses of misoprostol 4 hours apart 5
Expected Effects and Management
- Cramping and bleeding (expected and necessary)
- Bleeding lasts an average of 9-16 days 2
- Peak bleeding typically occurs 4-6 hours after misoprostol
- Side effects of misoprostol:
- Low-grade fever (common and transient)
- Gastrointestinal symptoms (nausea, vomiting, diarrhea)
- Management: NSAIDs for pain, antiemetics as needed 2
Follow-up Assessment
Timing
- 7-14 days after mifepristone administration
Confirmation of Complete Abortion
- Clinical history
- One or more of the following:
- Serial quantitative β-hCG levels showing appropriate decline
- Urine pregnancy testing (low-sensitivity test)
- Ultrasound confirmation if indicated 2
Management of Incomplete Abortion
- Additional dose of misoprostol may be considered
- Surgical evacuation if medical management fails or at patient request
Special Considerations
Post-Abortion Care
- Contraception counseling and provision
- Instructions for when to seek emergency care:
- Soaking 2 or more maxi pads per hour for 2 consecutive hours
- Severe abdominal pain unrelieved by analgesics
- Fever >100.4°F lasting more than 24 hours
Medical Abortion vs. Surgical Abortion
- Medical abortion has similar effectiveness to surgical abortion
- Higher rate of prolonged bleeding with medical abortion
- Surgical abortion may be preferred for patients:
- With medical contraindications to medical abortion
- Who desire immediate completion
- With limited follow-up access
Complications and Management
Potential Complications
- Ongoing pregnancy: 3.4% at 64-70 days 4
- Incomplete abortion: 1.6% at 64-70 days 4
- Infection requiring hospitalization: 0.01% 3
- Hemorrhage requiring transfusion: 0.03% 3
Management of Complications
- Ongoing pregnancy: Surgical evacuation (unless patient opts to continue pregnancy) 4
- Incomplete abortion: Additional misoprostol dose or surgical evacuation
- Infection: Appropriate antibiotics, possible hospitalization
- Hemorrhage: IV fluids, possible transfusion, surgical intervention if needed
Medical abortion using mifepristone and misoprostol is a safe and effective option with low rates of serious complications when performed according to established protocols and with appropriate patient selection.