Ovarian Hyperstimulation Syndrome

Rob Orman, MD and Brit Long, MD

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The summary below is from an episode of ERcast: Clinical Perspectives

Ovarian hyperstimulation syndrome is an iatrogenic complication of assisted reproductive technology driven by hCG-mediated capillary leak and third spacing. In the ED, it can look like benign abdominal bloating or progress to shock, AKI, PE, or ARDS, so recent fertility treatment is a key history question.

Recognizing OHSS in the ED

ART history clue: Recent assisted reproductive technology, especially IVF with ovarian stimulation, is the diagnostic clue that reframes abdominal pain, distention, and vomiting as possible OHSS rather than routine early-pregnancy complaints.
Capillary leak physiology: OHSS is fundamentally a VEGF-driven vascular permeability problem triggered by hCG, causing ascites, hemoconcentration, intravascular depletion, and a real thrombotic risk.
Typical presentation pattern: Abdominal pain, bloating, nausea, vomiting, and ascites are the common early findings, but tachycardia, dyspnea, or hypotension should push concern toward severe disease.
Fever and infection overlap: Fever is common in OHSS, but do not dismiss it as inflammatory noise alone; UTI, pneumonia, and even spontaneous bacterial peritonitis are on the table. We get into the bedside distinction in the episode.
Pelvic exam pitfall: Avoid a bimanual exam when OHSS is suspected because enlarged cystic ovaries can rupture or tors, turning a tenuous patient into a crashing one.

Severity and emergency management

Severity spectrum: Disease ranges from mild discomfort to critical illness with renal failure, dysrhythmias, DIC, pulmonary embolism, ARDS, or abdominal compartment syndrome.
Objective admission markers: Hemoconcentration matters: a hematocrit above 45% is a red flag for significant intravascular depletion and higher thrombotic risk, alongside AKI, transaminitis, and electrolyte derangements.
Resuscitation priorities: Severe OHSS is treated like mixed shock with careful IV fluids, electrolyte correction, early OB/GYN involvement, and norepinephrine when perfusion does not recover with volume alone.
Procedural pressure relief: Paracentesis, thoracentesis, and noninvasive ventilation can be pivotal when ascites or pleural fluid drives pain, dyspnea, or respiratory failure. We walk through where these fit in the chapter.
Medication cautions: Avoid NSAIDs and routine diuresis in significant OHSS because the problem is intravascular depletion despite dramatic third spacing, not simple fluid overload.

Subscribe to ERcast: Clinical Perspectives to listen to the episode.

References:

Timmons D, Montrief T, Koyfman A, Long B. Ovarian hyperstimulation syndrome: A review for emergency clinicians. Am J Emerg Med. 2019;37(8):1577-1584. PMID: 31097257

Faculty

Rob Orman, MD
Dr. Rob Orman is an emergency physician, educator, and executive coach specializing in physician performance and professional fulfillment. After more than 20 years in community emergency medicine, he now works with clinicians across specialties to address burnout, inefficiency, and career challenges. He earned his medical degree from Emory University School of Medicine and completed his residency at Denver Health Medical Center, where he served as chief resident. Dr. Orman is the founder of the Stimulus podcast and Orman Physician Coaching. He previously served as chief editor of ERcast and hosted Essentials of Emergency Medicine for nearly a decade.
Brit Long, MD
Dr. Brit Long is a Professor of Emergency Medicine at the University of Virginia and an emergency medicine physician with experience in both a community ED and at a military academic center ED. He is the Clinical Editor-in-Chief of emDOCs.His professional interests include medical education, evidence-based medicine, and the FOAMed movement. Outside of work, he enjoys spending time with his wife and two daughters