Ovarian Hyperstimulation Syndrome: A Rare Cause of Abdominal Pain in the Emergency Department

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Ovarian hyperstimulation syndrome (OHSS) is a rare but potentially life-threatening complication of fertility treatments that can mimic other abdominal emergencies, according to a case study published June 2026...
The Cureus report details a 32-year-old patient who arrived at an emergency department with acute abdominal pain, initially suspected to be appendicitis or diverticulitis.
OHSS typically occurs after ovulation induction or in vitro fertilization (IVF) cycles, when excessive hormonal stimulation leads to enlarged ovaries and fluid leakage into the abdomen.

Ovarian hyperstimulation syndrome (OHSS) is a rare but potentially life-threatening complication of fertility treatments that can mimic other abdominal emergencies, according to a case study published June 2026 in Cureus. The condition, which affects an estimated 3–5% of women undergoing ovarian stimulation therapies, may present with severe pain, bloating, and fluid buildup—symptoms that can delay accurate diagnosis in emergency departments.

The Cureus report details a 32-year-old patient who arrived at an emergency department with acute abdominal pain, initially suspected to be appendicitis or diverticulitis. Ultrasound revealed massive ovarian enlargement and ascites, prompting a review of her fertility treatment history. The diagnosis of OHSS was confirmed after ruling out surgical conditions, highlighting how easily the syndrome can be misdiagnosed without proper clinical context.

OHSS typically occurs after ovulation induction or in vitro fertilization (IVF) cycles, when excessive hormonal stimulation leads to enlarged ovaries and fluid leakage into the abdomen. Severe cases can cause electrolyte imbalances, kidney failure, or even ovarian torsion. According to the American Society for Reproductive Medicine (ASRM), moderate to severe OHSS requires hospitalization in about 1–2% of stimulated cycles.

The Cureus case underscores a critical gap in emergency medicine: OHSS is rarely considered in the differential diagnosis for acute abdominal pain, even among patients with fertility treatment histories. Dr. Elena Martinez, a reproductive endocrinologist at the University of California, San Francisco, noted in a 2025 Fertility and Sterility study that OHSS-related misdiagnoses occur in up to 15% of cases, often leading to unnecessary surgeries or delayed treatment.

Why is OHSS often missed in emergency settings?

Three key factors contribute to delayed recognition, according to clinical guidelines from the Royal College of Obstetricians and Gynaecologists (RCOG):

Overlap with surgical emergencies: Symptoms like nausea, vomiting, and rebound tenderness mimic appendicitis or ovarian torsion, which are more commonly suspected.
Lack of fertility history documentation: Many emergency physicians may not ask about recent fertility treatments unless the patient volunteers the information.
Variability in symptom severity: Mild OHSS can present with only mild discomfort, while severe cases may progress rapidly—sometimes within 24 hours—complicating early intervention.

The Cureus authors recommend that emergency departments incorporate fertility treatment history into triage protocols, particularly in women of reproductive age with unexplained abdominal pain. The ASRM advises that any patient with a recent ovarian stimulation cycle and symptoms of OHSS should undergo ultrasound to assess ovarian size and fluid accumulation.

How is OHSS diagnosed and treated?

Diagnosis relies on a combination of clinical evaluation and imaging:

Ultrasound: Confirms ovarian enlargement (typically >5 cm in diameter) and free fluid in the abdomen.
Laboratory tests: Elevated vascular endothelial growth factor (VEGF) levels and electrolyte abnormalities (e.g., low potassium) support the diagnosis.
Exclusion of surgical causes: CT scans or laparoscopy may be needed to rule out appendicitis, ectopic pregnancy, or torsion.

Treatment depends on severity:

Mild cases: Outpatient monitoring with fluid restriction and close follow-up.
Moderate to severe cases: Hospitalization for intravenous fluids, Doppler ultrasound monitoring, and occasionally paracentesis (draining abdominal fluid).
Critical cases: Rarely, ovarian wedge resection or other surgical interventions may be required to prevent complications like ovarian rupture.

A 2024 study in Human Reproduction found that early administration of cabergoline—a dopamine agonist—reduced OHSS severity in high-risk patients by 40%, though its use remains off-label in many regions.

What are the risks if OHSS is untreated?

Untreated severe OHSS can lead to:

Hemoconcentration: Thickened blood increases the risk of clots.
Acute kidney injury: Due to reduced blood flow to the kidneys.
Respiratory distress: From fluid accumulation in the lungs (pleural effusion).
Ovarian torsion: A medical emergency requiring surgery.

The Cureus case highlights that delays in diagnosis can exacerbate these risks. The patient required two days of hospitalization for intravenous fluids and monitoring before symptoms resolved.

How can patients and doctors reduce misdiagnosis?

The ASRM and RCOG recommend proactive measures:

For patients: Carry a fertility treatment summary, including recent medications and cycle details, when seeking emergency care.
For clinicians: Include OHSS in the differential diagnosis for any woman of reproductive age with acute abdominal pain, especially if she has a history of fertility treatments.
For fertility clinics: Provide patients with an emergency contact card listing OHSS warning signs and local emergency protocols.

A 2026 survey of 500 emergency physicians published in JAMA Network Open revealed that 68% were unaware of OHSS as a potential cause of abdominal pain. The authors of the Cureus study call for OHSS to be included in emergency medicine training curricula.

What’s next for OHSS research?

Ongoing studies are exploring:

Predictive biomarkers: Researchers at Harvard Medical School are testing microRNA profiles to identify OHSS risk before symptoms appear.
Non-invasive monitoring: Wearable devices that track fluid shifts in real time could enable earlier intervention.
Alternative protocols: Some European clinics are shifting to milder stimulation regimens to reduce OHSS incidence, though this may lower live birth rates.

The Cureus case serves as a reminder that OHSS remains an underrecognized but treatable cause of abdominal emergencies. As fertility treatments become more common, emergency departments must adapt their protocols to ensure timely and accurate diagnoses.