Ovarian Hyperstimulation Syndrome

Key considerations: Ovarian torsion (enlarged stimulated ovaries at higher risk), Ectopic pregnancy in IVF patients, Pulmonary embolism (hypercoagulable state)

Cannot miss

Ovarian torsion (enlarged stimulated ovaries at higher risk)
Ectopic pregnancy in IVF patients
Pulmonary embolism (hypercoagulable state)

Likely diagnoses

Mild OHSS
Moderate OHSS
Severe OHSS
Ovarian torsion complicating OHSS

Red flags

Severe abdominal pain and distension
Rapid weight gain (>1kg/day)
Decreased urine output
Dyspnea (pleural effusion/ascites)
Nausea/vomiting preventing oral intake
Ovarian enlargement >12cm

Workup

history: IVF/fertility treatment history, timing in cycle, symptoms onset, weight changes, urine output; exam: Abdominal distension, ascites assessment, respiratory status, weight; labs: CBC (hemoconcentration — Hct >45% severe), BMP, LFTs, coags, hCG (pregnancy status); imaging: Pelvic ultrasound (ovarian size, ascites, pleural effusion); bedside: Daily weights, strict I&Os, oxygen saturation

Management

immediate: Moderate-severe: IV fluid resuscitation (albumin preferred over crystalloid); general: Mild: outpatient — oral hydration, daily weights, avoid strenuous activity; Thromboprophylaxis (enoxaparin — high VTE risk) for moderate-severe; Paracentesis/thoracentesis for symptomatic effusions; Dopamine for oliguria; Antiemetics, analgesia

Disposition

admit: Moderate-severe OHSS, Hct >45%, renal impairment, respiratory compromise; discharge: Mild OHSS with daily outpatient follow-up; consults: REI (reproductive endocrinology), pulmonology if respiratory compromise

Clinical pearls

OHSS is almost exclusively seen in IVF patients and resolves spontaneously in non-pregnant patients within 1-2 weeks
If pregnancy occurs, OHSS can worsen significantly in first trimester due to rising hCG
Albumin is preferred over crystalloid for volume expansion — crystalloid leaks into third space worsening ascites

Source and review

ASRM OHSS Prevention and Treatment 2021. Last reviewed: 2024-11-01