Recommended Dose of Mifepristone for Medical Termination of Pregnancy (MTP)
The recommended dose of mifepristone for medical termination of pregnancy is 200 mg orally as a single dose, followed by misoprostol administration 36-48 hours later. 1, 2
Dosing Protocol for MTP
- The standard regimen includes 200 mg of oral mifepristone, followed by 800 mcg of misoprostol administered buccally or vaginally 36-48 hours later 2
- Although 600 mg was the original recommended dose, clinical evidence shows that 200 mg is equally effective for pregnancy termination 1
- This regimen is effective for early pregnancy termination up to 63 days (9 weeks) of amenorrhea 3
- The timing between mifepristone and misoprostol administration is important - the standard 36-48 hour interval is significantly more effective than shorter intervals 4
Efficacy Based on Gestational Age
- Efficacy decreases with advancing gestational age: 3
- ≤49 days: 92% success rate
- 50-56 days: 83% success rate
- 57-63 days: 77% success rate
Administration Guidelines
- Mifepristone should be administered as a single oral dose 5
- The tablet should be swallowed whole (not split, crushed, or chewed) 5
- A negative pregnancy test must be confirmed before initiating treatment 5
- For second trimester termination (12-20 weeks), the same dose of 200 mg mifepristone is used, followed by a different misoprostol regimen 6
Mechanism of Action
- Mifepristone acts as a potent antagonist of progesterone, binding to cytosolic progesterone receptors and preventing gene transcription 7, 5
- This antiprogestational effect results in:
Expected Effects and Monitoring
- Cramping and bleeding are expected effects, with bleeding lasting an average of 9-16 days 2
- Common side effects include nausea, vomiting, diarrhea, and abdominal pain 3
- Rare complications include ongoing pregnancy, infection, hemorrhage, and need for unplanned uterine aspiration 2
Important Considerations and Contraindications
- Mifepristone should be avoided in patients with severe hepatic impairment 5
- Dose adjustment is necessary when used with strong CYP3A inhibitors 5
- Surgical evacuation (dilatation and evacuation) remains the safest procedure for high-risk patients 8
- Misoprostol should be avoided in women with previous cesarean delivery due to risk of uterine rupture 8
Follow-up and Confirmation of Complete Abortion
- Follow-up is essential to confirm complete passage of pregnancy tissue 2
- This can be done through clinical history combined with:
- Serial quantitative beta-hCG levels
- Urine pregnancy testing
- Ultrasonography 2
The combination of mifepristone and misoprostol has been established as a safe and effective regimen for medical termination of pregnancy when administered at the recommended doses and intervals.