A 32-year-old woman with a positive urine pregnancy test at home attends the antenatal clinic. She is uncertain about her last menstrual period (LMP). Transvaginal ultrasound shows a gestational sac of 8 mm with no yolk sac. What is the drug of choice for medical management if she opts for termination of pregnancy at this stage?

Question

Accepted Answer

D. Mifepristone followed by misoprostol. ## Medical Management of Early Pregnancy Termination

**Key Point:** Mifepristone (progesterone antagonist) followed by misoprostol (prostaglandin analogue) is the gold-standard regimen for medical termination of pregnancy in the first trimester.

### Clinical Context
At 8 mm gestational sac (approximately 5–6 weeks gestation), the patient is within the window for medical management of early pregnancy loss or termination.

### Mifepristone + Misoprostol Regimen

1. **Mifepristone 200 mg orally** — blocks progesterone receptors, leading to endometrial decidualization loss and detachment of trophoblast
2. **Wait 36–48 hours**
3. **Misoprostol 800 μg (vaginally, buccally, or sublingually)** — induces uterine contractions and cervical ripening
4. **Success rate:** 95–98% with complete expulsion

### Mechanism of Action

```mermaid
flowchart TD
  A[Mifepristone 200 mg PO]:::action --> B[Blocks PR receptors]:::outcome
  B --> C[Endometrial decidualization loss]:::outcome
  C --> D[Trophoblast detachment]:::outcome
  D --> E[Wait 36-48 hrs]:::action
  E --> F[Misoprostol 800 μg]:::action
  F --> G[Uterine contractions + cervical ripening]:::outcome
  G --> H[Complete expulsion]:::outcome
```

### Comparison of Regimens

| Regimen | Efficacy | Timing | Advantages | Disadvantages |
|---------|----------|--------|------------|---------------|
| Mifepristone + Misoprostol | 95–98% | 3–7 days | Gold standard, highest efficacy, lower infection risk | Requires 2 visits, cost |
| Misoprostol alone | 60–80% | 7–14 days | Single agent, lower cost | Lower efficacy, longer duration, higher bleeding |
| Methotrexate + Misoprostol | 85–90% | 7–14 days | Alternative if mifepristone unavailable | Slower, teratogenic if pregnancy continues |
| Oxytocin | <50% | Variable | Rarely used alone | Ineffective without cervical ripening |

**High-Yield:** Mifepristone + misoprostol is the WHO-recommended first-line regimen for medical termination up to 9 weeks gestation; it has the highest efficacy and lowest complication rate.

**Clinical Pearl:** The combination works synergistically — mifepristone sensitizes the myometrium to prostaglandins, making misoprostol far more effective than when used alone.

**Warning:** Misoprostol monotherapy (option 2) has only 60–80% efficacy and is NOT first-line; methotrexate (option 3) is slower and reserved for cases where mifepristone is unavailable or contraindicated.

**Mnemonic:** **MIM** — **M**ifepristone, **I**nterval 36–48 hrs, **M**isoprostol — the gold-standard triad for early medical termination.

[cite:Williams Obstetrics 26e Ch 18; RCOG Guideline on Medical Management of Abortion]

Answer

A. Methotrexate followed by misoprostol

Answer

B. Misoprostol alone

Answer

C. Oxytocin infusion

Explanation

Medical Management of Early Pregnancy Termination

Clinical Context

Mifepristone + Misoprostol Regimen

Mechanism of Action

Comparison of Regimens

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Regimen	Efficacy	Timing	Advantages	Disadvantages
Mifepristone + Misoprostol	95–98%	3–7 days	Gold standard, highest efficacy, lower infection risk	Requires 2 visits, cost
Misoprostol alone	60–80%	7–14 days	Single agent, lower cost	Lower efficacy, longer duration, higher bleeding
Methotrexate + Misoprostol	85–90%	7–14 days	Alternative if mifepristone unavailable	Slower, teratogenic if pregnancy continues
Oxytocin	<50%	Variable	Rarely used alone	Ineffective without cervical ripening