A 28-year-old woman presents with vaginal bleeding and lower abdominal pain 8 weeks after a spontaneous abortion. Ultrasound shows a heterogeneous mass filling the uterine cavity with abnormal vascularity on Doppler. β-hCG is 85,000 mIU/mL. What is the most appropriate next step in management?

Explanation

## Clinical Scenario Analysis This patient presents with a post-evacuation molar pregnancy (persistent gestational trophoblastic disease). The key clinical features are: - Vaginal bleeding and abdominal pain 8 weeks post-abortion - Ultrasound: heterogeneous uterine mass with abnormal vascularity - Markedly elevated β-hCG (85,000 mIU/mL) These findings are consistent with **persistent gestational trophoblastic neoplasia (GTN)**, not uncomplicated molar pregnancy. ## Management Algorithm for GTN ```mermaid flowchart TD A[Diagnosis of GTN suspected]:::outcome --> B[Obtain staging investigations]:::action B --> C[Chest X-ray, pelvic MRI/CT]:::action C --> D[Calculate FIGO risk score]:::decision D -->|Low risk| E[Single-agent chemotherapy]:::action D -->|High risk| F[Combination chemotherapy]:::action E --> G[Monitor β-hCG weekly]:::action F --> G ``` ## Why Staging Before Chemotherapy? **Key Point:** Before initiating any chemotherapy for GTN, **complete staging and risk stratification are mandatory**. This determines: 1. Whether the disease is localized or metastatic 2. Prognostic risk group (low vs. high) 3. Choice of chemotherapy regimen **High-Yield:** FIGO risk score incorporates: - Age, type of antecedent pregnancy, interval from evacuation - β-hCG level, largest tumor size, sites of metastasis - Prior failed chemotherapy **Clinical Pearl:** A β-hCG >85,000 mIU/mL and 8-week interval post-evacuation are already high-risk features. Imaging is essential to exclude metastatic disease before treatment planning. ## Why NOT the Other Options? | Option | Why Incorrect | |--------|---------------| | **Immediate D&C/suction evacuation** | GTN requires chemotherapy, not repeat evacuation. D&C is appropriate only for initial molar pregnancy evacuation, not for persistent/invasive disease. Repeat instrumentation increases bleeding risk and does not address systemic disease. | | **Start methotrexate immediately** | Premature initiation without staging. Methotrexate is single-agent therapy for low-risk GTN only. High-risk disease (suggested by β-hCG level) requires combination regimens (EMA/CO or BEP). | | **Mifepristone + misoprostol** | Medical evacuation is used for early pregnancy loss or uncomplicated molar pregnancy evacuation, NOT for established GTN. This patient has already had evacuation; she has persistent/invasive disease requiring chemotherapy. | **Tip:** Always remember the GTN management sequence: **Evacuate → Stage → Risk-stratify → Treat**. This patient is past evacuation; she is at the staging phase.