What are the abortion-inducing drugs, their typical dosages, and potential risks for a patient considering medical abortion?

Medical Abortion Medications and Protocols

Primary Medication Regimen

The standard evidence-based medical abortion regimen consists of 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 with a 97.7% success rate. 1, 2

Mifepristone (Progesterone Receptor Antagonist)

• Dose: 200 mg orally on day 1 1, 3, 2
• Mechanism: Causes luteolysis and prepares the uterus for expulsion 4
• Efficacy: The 200 mg dose is as effective as the previously used 600 mg FDA-approved dose 3

Misoprostol (Prostaglandin E1 Analogue)

• Dose: 800 mcg administered 24-48 hours after mifepristone 1, 2
• Route options: Buccal or vaginal administration 1
• Timing flexibility: Can be administered simultaneously with mifepristone (95.1% efficacy) or 24 hours later (96.9% efficacy), though the 24-hour interval is standard 5
• Self-administration: Can be safely self-administered at home 3, 2

Efficacy by Gestational Age

The success rate varies by gestational age 2:

• 29-35 days: 98.8% efficacy 2
• 36-42 days: 98.8% efficacy 2
• 57-63 days: 95.5% efficacy 2
• Overall through 63 days: 97.7% complete abortion rate 2

Expected Effects and Timeline

Bleeding Pattern

• Onset: 80% of women begin bleeding within 4 hours of misoprostol use; 98% within 24 hours 3
• Duration: Average bleeding lasts 9-16 days 1
• Completion: 95% of women achieve complete abortion by day 7 3
• Peak expulsion: Half of patients pass the pregnancy within the first few hours after misoprostol administration 4

Common Side Effects from Misoprostol

• Low-grade fever 1
• Gastrointestinal symptoms (nausea, diarrhea) 1, 5
• Warmth or chills 5
• Cramping (expected therapeutic effect) 1
• Management: NSAIDs or antiemetics effectively control these symptoms 1

Potential Risks and Complications

Serious Complications (Rare)

• Hemorrhage requiring transfusion: 0.03% 2
• Infection requiring hospitalization: 0.01% 2
• Ongoing pregnancy: Rare, occurs in approximately 2-3% of cases 1, 2
• Undiagnosed ectopic pregnancy: Rare but must be excluded before treatment 1
• Need for surgical intervention: 2-10% may require uterine aspiration for any indication 4, 2

Distinguishing Normal from Abnormal Bleeding

• Expected: Bleeding averaging 14 days with gradual decrease 4
• Concerning: Hemorrhage requiring intervention occurs in 2-10% and necessitates surgical abortion 4

Essential Pre-Treatment Requirements

Gestational Age Confirmation

• Methods: Ultrasonography or reliable menstrual history 1
• Ultrasonography mandatory when: Dating cannot be confirmed clinically or risk factors for ectopic pregnancy exist 1
• Maximum gestational age: Up to 63 days (9 weeks) from last menstrual period 1, 2

Provider Capabilities Required

• Ability to diagnose ectopic pregnancies 4
• Arrangements for surgical abortion backup in case of failure or emergencies 4
• Access to follow-up evaluation methods 4, 1

Follow-Up and Confirmation of Completion

Verification Methods

• Clinical history combined with one of the following 1:
  • Serial quantitative beta-hCG levels 1
  • Urine pregnancy testing 1
  • Ultrasonography 1
• Timing: Follow-up evaluation 7±1 days after initiating treatment 5
• Second dose option: Women who have not aborted by first follow-up can receive a second misoprostol dose 5

Tissue Examination Considerations

• Pregnancy may pass spontaneously without tissue obtained for confirmation 4
• Physicians must be aware of state-specific requirements regarding expelled tissue examination 4

Critical Management for Rh-Negative Patients

All Rh-negative women undergoing medical abortion must receive RhD immune globulin (RhIg) within 72 hours, as fetal red blood cells display RhD antigens from as early as 6 weeks of gestation. 6, 7, 8

• Dose for first trimester: 50 μg RhIg is adequate for losses up to 12 weeks 6, 7, 8
• Alternative: If 50 μg unavailable, use standard 300 μg dose 6
• Rationale: Prevents RhD alloimmunization that can cause devastating fetal outcomes in subsequent pregnancies 6

Alternative Regimen

Methotrexate-Based Protocol

• Methotrexate can be used as an alternative medication regimen for medical abortion 4
• This option can safely expand choices and reduce expense 4
• Specific dosing protocols exist but are less commonly used than mifepristone/misoprostol 4

Common Pitfalls to Avoid

• Do not delay RhIg administration based on early gestational age—sensitization is possible from 6 weeks onward 6, 7
• Do not assume minimal bleeding excludes the need for follow-up—ongoing pregnancy occurs in 2-3% of cases 1, 2
• Do not use the outdated FDA-approved 600 mg mifepristone dose—200 mg is equally effective and evidence-based 3, 2
• Do not fail to exclude ectopic pregnancy before initiating medical abortion when risk factors exist 1
• Do not withhold antiemetics or NSAIDs—these effectively manage expected side effects and improve patient comfort 1