USMLE Prep - Medical Reference Library

Ectopic Pregnancy — Diagnosis & Management

System: Obstetrics Gynecology • Reviewed: Aug 31, 2025 • Step 1Step 2Step 3

Synopsis:

Consider in any reproductive age patient with abdominal pain or bleeding; use TVUS and serial hCG; methotrexate for selected stable cases; surgery for instability, rupture, or contraindications to methotrexate.

Key Points

  • Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
  • Use system-specific risk tools to guide testing and disposition.
  • Order high-yield tests first; escalate imaging when indicated.
  • Start evidence-based initial therapy and reassess frequently.

Algorithm

  1. Primary survey and vitals; IV access and monitors.
  2. Focused history/physical; identify red flags and likely etiologies.
  3. Order system-appropriate labs and imaging (see Investigations).
  4. Initiate guideline-based empiric therapy (see Pharmacology).
  5. Reassess response; arrange consultation and definitive management.

Clinical Synopsis & Reasoning

For Ectopic Pregnancy Dx Mgmt, frame the differential by acuity and pathophysiology, then align diagnostics to the leading hypotheses. Prioritize stabilization while obtaining high‑yield studies such as CBC (Baseline hematology), BMP (Electrolytes/renal). Incorporate bedside imaging and targeted labs to define severity and identify complications; synthesize results with clinical trajectory to refine the working diagnosis and disposition needs.


Treatment Strategy & Disposition

Initiate disease‑directed therapy alongside supportive care, titrating to objective response. Pharmacologic options commonly include Analgesia/Antipyretics. Use validated frameworks (e.g., Methotrexate Selection (Abbrev.)) to guide escalation and site of care. Address precipitating factors, de‑escalate empiric therapies with data, and arrange follow‑up for monitoring and risk‑factor modification; admit patients with instability, high risk of deterioration, or needs for close monitoring.


Epidemiology / Risk Factors

  • Risk factors vary by condition and patient profile

Investigations

TestRole / RationaleTypical FindingsNotes
CBCBaseline hematologyAbnormal counts
BMPElectrolytes/renalDerangements

Methotrexate Selection (Abbrev.)

CriterionTypical Requirement
Hemodynamic statusStable
hCG levelLower levels have higher success
UltrasoundNo significant hemoperitoneum; no fetal cardiac activity
ReliabilityAdherence to follow up required

Pharmacology

MedicationMechanismOnsetRole in TherapyLimitations
Methotrexate (selected)DHF reductase inhibitionDaysMedical management for selected stable casesHepatotoxicity; teratogenic; pregnancy/lactation considerations
Rh(D) immune globulinAnti-D antibodiesHoursRh-negative patientsInjection reaction; pregnancy/lactation considerations

Prognosis / Complications

  • Prognosis depends on severity, comorbidities, and timeliness of care

Patient Education / Counseling

  • Explain red flags and when to seek emergent care.
  • Reinforce medication adherence and follow-up plan.

Notes

Avoid methotrexate with renal or hepatic failure, breastfeeding, or significant hematologic abnormalities. Counsel on ectopic rupture warning signs.


References

  1. ACOG Practice Bulletin — Ectopic Pregnancy — Link
  2. ACEP Clinical Policy — Early Pregnancy — Link