What is the procedure for a medical abortion using misoprostol (prostaglandin E1 analog)?

Medical Abortion Using Misoprostol: Procedure and Protocol

Optimal Regimen Selection

The most effective approach for medical abortion is the combination of mifepristone 200 mg orally followed by misoprostol 800 mcg (vaginally or buccally), which achieves 95-97% complete abortion rates through 63 days of gestation. 1, 2, 3

Combined Mifepristone-Misoprostol Protocol (Preferred)

• Mifepristone 200 mg orally is administered first, which blocks progesterone action necessary to sustain pregnancy 4

• Misoprostol 800 mcg follows via vaginal, buccal, or sublingual route 1, 2, 3

• Timing options include:

  • Simultaneous administration (misoprostol immediately after mifepristone) achieves 95.1% efficacy 2
  • 24-hour interval (traditional approach) achieves 96.9% efficacy 2
  • 36-48 hour interval is also effective 5

• Route selection considerations:

  • Vaginal administration: 93% efficacy, fewer gastrointestinal side effects 3
  • Buccal administration: 95% efficacy, equally acceptable to patients 3
  • Sublingual route: more gastrointestinal symptoms (nausea, diarrhea, warmth/chills) 6, 3

Misoprostol-Only Protocol (When Mifepristone Unavailable)

• Misoprostol 800 mcg vaginally is the standard dose for first-trimester medical management of miscarriage 7

• Higher doses beyond 800 mcg per administration do not improve outcomes and may increase complications such as uterine hyperstimulation 6

• This regimen is less effective than combined therapy and requires higher total doses 8

Gestational Age-Specific Protocols

First Trimester (Up to 9-12 weeks)

• Medical abortion can be performed in outpatient or home settings before 9 weeks 1

• The combined regimen (mifepristone + misoprostol) is highly effective through 63 days (9 weeks) of gestation 2

• Success rates remain consistent across gestational ages within the first trimester 2

Second Trimester (12-20 weeks)

• Mifepristone 200 mg orally followed 36-48 hours later by misoprostol 800 mcg vaginally 5

• Repeat dosing: Misoprostol 400 mcg vaginally every 3 hours (maximum 4 doses in 24 hours) 5

• Median induction-to-abortion interval is 6.7 hours, with 97.9% completing within 24 hours 5

• Second trimester procedures should occur in facilities with blood transfusion and emergency surgery capabilities, as these cases account for two-thirds of major abortion-related complications despite representing only 10-15% of all abortions 8

• Critical safety consideration: Dilatation and evacuation (D&E) is the safest surgical procedure for both first and second trimesters 9, 1

Absolute Contraindications

Misoprostol is absolutely contraindicated in women with prior cesarean delivery due to 13% risk of uterine rupture. 6, 10

• Previous uterine surgery or scar significantly increases rupture risk 10, 8

• Grand multiparity is an additional risk factor for uterine rupture 10

• The risk of uterine rupture increases with advancing gestational age 10

Expected Side Effects and Management

• Common side effects include gastrointestinal symptoms (nausea, vomiting, diarrhea), fever/rigors, and pain 7

• Sublingual route causes more gastrointestinal symptoms than vaginal administration 6

• Nausea affects 62-70% of patients regardless of route 3

• Pain management should be proactive, as nulliparous women experience more pain than multiparous women 5

Critical Safety Monitoring

Cardiovascular Considerations

• Misoprostol (prostaglandin E1 analog) can lower systemic vascular resistance and blood pressure while increasing heart rate 9

• In high-risk cardiac patients, systemic arterial oxygen saturation should be monitored with pulse oximetry 9

• Norepinephrine infusion may be needed to support diastolic blood pressure (which reflects systemic vascular resistance) 9

Infection Recognition

• Do not wait for fever to diagnose intrauterine infection - clinical symptoms may be subtle in early gestations 1

• Warning signs include maternal tachycardia, purulent cervical discharge, uterine tenderness, and fetal tachycardia 1

• If infection is suspected, initiate broad-spectrum antibiotics immediately and proceed with urgent surgical evacuation 1

Follow-Up and Completion Assessment

• Follow-up evaluation with transvaginal ultrasound should occur 7±1 days after treatment initiation 2

• If abortion is incomplete, a second dose of misoprostol may be offered 2

• Surgical evacuation (vacuum aspiration) is indicated if medical management fails or for profuse bleeding 1

• Surgical evacuation rate is approximately 5% for incomplete abortion or retained placenta 5

Essential Preventive Measures

• All Rh-negative women must receive anti-D immunoglobulin (50 mcg dose) to prevent alloimmunization, as fetomaternal hemorrhage occurs in 32% of spontaneous abortions 1

• Contraceptive counseling should be provided immediately, as ovulation can resume within 2-4 weeks post-abortion 1

• Combined hormonal contraceptives or implants can be initiated immediately without waiting for next menses 1

Common Pitfalls to Avoid

• Never use expectant management for confirmed fetal demise - it carries 60.2% maternal morbidity versus 33% with active abortion care, with significantly higher rates of infection (38% vs 13%) and hemorrhage (23.1% vs 11%) 1

• Do not delay treatment waiting for fever if infection is suspected clinically 1

• Avoid prostaglandin F compounds, as they can increase pulmonary artery pressure and decrease coronary perfusion 9

• Avoid saline abortion methods due to risk of intravascular volume expansion, heart failure, and clotting abnormalities 9