A 28-year-old woman at 6 weeks gestation presents with severe right lower quadrant pain and vaginal bleeding. Transvaginal ultrasound shows an empty uterus with a 3 cm mass in the right adnexa containing a yolk sac but no primitive streak or embryonic disc. Free fluid is present in the pelvis. What is the most appropriate immediate next step?

Explanation

## Ectopic Pregnancy with Hemodynamic Compromise This clinical presentation describes a **ruptured ectopic pregnancy** — the embryo has implanted outside the uterus (in the fallopian tube) and failed to develop a primitive streak and axial structures within the uterine cavity. The presence of a yolk sac in the adnexa confirms extrauterine implantation; the absence of primitive streak reflects early gestational age or abnormal development. ### Key Distinguishing Features | Feature | Ectopic Pregnancy | Intrauterine Miscarriage | |---------|-------------------|------------------------| | **Gestational sac location** | Adnexa (tube, ovary, cervix) | Uterine cavity | | **Yolk sac presence** | May be present (confirms intrauterine) | May be present | | **Free fluid in pelvis** | Blood (rupture) | Minimal or absent | | **Hemodynamic status** | Often unstable (rupture) | Usually stable | | **hCG level** | Often lower than expected for dates | Variable | ### Why Immediate Serum Testing + Surgical Prep is Correct **Key Point:** A patient with severe pain, vaginal bleeding, free fluid, and hemodynamic instability (implied by "severe" pain) has a **ruptured or rupturing ectopic pregnancy** — a surgical emergency. **High-Yield:** The immediate next step is: 1. **Confirm viability status** with β-hCG and progesterone (rapid turnaround) 2. **Prepare for emergency surgery** (type & cross, NPO, anesthesia consult) 3. **Do NOT delay surgery for imaging or medical management** — rupture is life-threatening **Clinical Pearl:** Free fluid + adnexal mass + empty uterus + hemodynamic instability = **presumed ruptured ectopic until proven otherwise**. Surgery is indicated regardless of hCG level. ### Management Flowchart ```mermaid flowchart TD A[Ectopic pregnancy suspected]:::outcome --> B{Hemodynamically stable?}:::decision B -->|No/Unstable| C[Severe pain, free fluid, bleeding]:::urgent C --> D[Stat hCG + progesterone]:::action D --> E[Emergency surgical prep]:::action E --> F[Laparoscopy or laparotomy]:::action B -->|Yes/Stable| G{hCG level?}:::decision G -->|Low, declining| H[Expectant or medical management]:::action G -->|Rising| I[Laparoscopy + salpingostomy]:::action ``` **Tip:** Methotrexate is reserved for hemodynamically stable patients with unruptured ectopic pregnancy and hCG < 5000 mIU/mL; it is contraindicated in rupture or instability.