A 28-year-old woman with a positive urine pregnancy test presents with acute lower abdominal pain and vaginal bleeding. Transvaginal ultrasound shows no intrauterine gestational sac but a 3 cm mass in the left adnexa with free fluid in the pelvis. Which single feature best distinguishes a ruptured ectopic pregnancy from an unruptured ectopic pregnancy?

Explanation

## Distinguishing Ruptured from Unruptured Ectopic Pregnancy ### Clinical Presentation Comparison | Feature | Unruptured Ectopic | Ruptured Ectopic | |---------|-------------------|------------------| | **Hemodynamic status** | Stable or mildly symptomatic | Acute shock, severe hypotension | | **Free fluid** | May be present (small amount) | Massive hemoperitoneum | | **Abdominal pain** | Mild to moderate | Severe, acute onset | | **Vaginal bleeding** | Mild, watery | Heavy | | **Vital signs** | Normal or near-normal | Tachycardia, hypotension | **Key Point:** Hemodynamic instability with acute hemorrhagic shock is the hallmark discriminator of rupture. An unruptured ectopic may have free fluid, elevated hCG, and absent intrauterine sac—but these are shared features. ### Why Rupture Matters **High-Yield:** Rupture occurs when the growing trophoblast erodes through the tubal wall, causing massive intra-abdominal hemorrhage. This is a **surgical emergency** requiring immediate intervention. **Clinical Pearl:** A patient with ruptured ectopic may lose 1–2 L of blood into the peritoneal cavity before presenting in frank hypovolemic shock. Unruptured ectopics, by contrast, remain hemodynamically compensated until rupture occurs. ### Why the Other Options Are Shared Features - **Free fluid in pelvis:** Present in both unruptured (small amount from tubal secretion) and ruptured (massive blood) ectopics. - **Elevated β-hCG:** Both produce hCG; level does not predict rupture status. - **Absent intrauterine sac:** Diagnostic of ectopic pregnancy but does not distinguish rupture from non-rupture. [cite:Jeffcoate's Principles of Gynaecology Ch 8]