OHSS

Question 1

OHSS differential diagnoses

Answer 1

• ovarian torsion
• ectopic pregnancy
• heterotopic pregnancy (increased w IVF)
• ovarian cyst rupture/haemorrhage
• PID/TOA
• appendicitis, pyelonephritis, cholecystitis, pyelonephritis, renal colic, bowel obstruction, constipation/ileus

Question 2

IVF-cycle risk factors for OHSS

Answer 2

• hCG trigger or hcg luteal support (Vs GnRH agonist trigger)
• High ovarian response: high E2/many follicles/high oocyte yield
• Fresh embryo transfer vs freeze all = high risk
• PCOS/high AFC
• Pregnancy in the stimulation cycle -> late OHSS
• younger age/low BMI

Question 3

How do TVUS and FBC help severity assessment of OHSS?

Answer 3

• FBC: haemoconcentration (↑Hct/Hb) tracks third spacing/severity; leukocytosis common but nonspecific.
• TVUS: ovarian enlargement and volume of ascites correlate with severity; also assess for complications (torsion, ectopic, cyst rupture).

Question 4

Management principles of OHSS

Answer 4

• Assess and monitor: vitals, weight, abdominal girth, fluid balance chart (input/output), UEC, Hct, outpatient vs admit based on severity
• Supportive: oral/IV crystalloids to maintain perfusion; antiemetics (ondansetron/metoclopramide), analgesia (avoid NSAIDs if renal risk/pregnancy), PPI if needed; correct electrolytes
• VTE prophylaxis: LMWH for moderate-severe OHSS; mobilise
• Drainage: US-guided paracentesis for tense ascites/respiratory compromise; manage pleural effusion as indicated
• Med options: consider cabergoline early to reduce VEGF- mediated permeability (unit policy); albumin in selected cases
• Escalate/ICU for oliguria/AKI, rising Hct/Cr, dyspnoea/hypoxia, haemodynamic instability, VTE
• Avoid hCG exposure; coordinate with fertility team; if prengant, consider progesterone only luteal support

Question 5

When to escalate to ICU/CCU (OHSS)

Answer 5

• Hypoxia/respiratory compromise (tense ascites/pleural effusions)
• Haemodynamic instability/AKI

Question 6

What is the mechanism in OHSS for Haemoconcentration + weight gain + oliguria

Answer 6

• Significant third spacing -> ascites, oedema, pleural effusions + reduced intravascular volume (reduced oncotic pressure) + reduced perfusion of kidneys.
• Use goal-directed fluids to maintain perfusion/UO (~0.5 mL/kg/h), avoid overload; drain ascites as needed.