Dr Nick Erskine

Emergency Registrar

Peer review: Dr Katie Waldman


A 30-year old woman presents to your Emergency Department complaining of mild abdominal discomfort and exertional dyspnoea. She feels well and doesn’t particularly want to be in hospital, but was told to present by her fertility team as she had recently commenced in-vitro fertilisation.

Clinically, she is well with normal vital signs. There’s no respiratory distress or increased work of breathing, and having managed to find a stethoscope somewhere in the department, you think she has reduced air entry at both bases. Her abdomen is soft and slightly tender in the lower quadrants without guarding or rigidity. There is no pedal oedema.

A standard “abdominal pain fishing-trip” panel of bloods have been taken, outlined below:

Hb 175 (H)
HCT 0.5 (H)
MCH 30
MCV 85
Platelets 340
WCC 19.0 (H)
Neut 17.5 (H)
Lymph 1.0
Na 130 (L)
K 4.5
Cl 105
HCO3 22
Urea 4.2
Cr 80
eGFR 83
Glucose 5.8
Albumin 29 (L)
Bili 15
ALT 65
GGT 30
ALP 60
Lipase 40
CRP 10
hCG 25 (H)
What is the diagnosis?

Ovarian Hyperstimulation Syndrome (OHSS)

Yeah, but what exactly is that?
A complication of IVF treatment due to an excessive response to ovarian follicle stimulation. The exact pathogenesis is unknown, though a number of vasoactive substances have been implicated in the pathway – TNF-alpha, interleukins, endothelin-1, vascular endothelial growth factor[1].

Whatever the culprit, the end result is increased vascular permeability causing third space fluid losses and intravascular depletion – particularly ascites, pleural effusions, and peripheral oedema. Rarely it can also cause pericardial effusions and cerebral oedema.

What are the common symptoms?
  • Lower abdominal pain, bloating, nausea and vomiting.
    • These can be directly related to ovarian stimulation and follicle growth, or a sign of developing ascites.
  • Shortness of breath and decreased exercise tolerance due to pulmonary oedema or pleural effusions.
  • Peripheral oedema (including vulval oedema)
  • Confusion from cerebral oedema (less common)
What are the risk factors?
Patient factors
    • Relative youth ( < 30 years)
    • Low BMI
    • PCOS
    • Increased ovarian volume and high follicle count on baseline scan
    • Elevated baseline anti-mullerian hormone
    • Previous OHSS


IVF procedure factors
    • GnRH agonist ovarian stimulation (OHSS rate 3-8%, compared to GnRH antagonist IVF ~1%)
    • High treatment doses of follicle stimulating hormone
    • Large number of oocytes collected (>20)
    • Rapidly rising / high oestrogen levels[2]
What are the complications?
Fluid distribution
    • Intra-vascular depletion
    • Pleural effusions
    • Pulmonary Oedema or ARDS
    • Ascites
    • Cerebral oedema
    • Pericardial effusion
Subsequent biochemical derangement
    • Hypo-osmolar hyponatraemia
    • Hyperkalaemia
    • Hypoalbuminaemia / hypoproteinaemia
    • Pre-renal acute kidney injury / renal failure
Thromboembolic events
    • DVT
    • PE
    • Arterial thrombosis
    • Stroke
Ovarian follicle growth
    • Ovarian torsion

It’s time to get the ultrasound out!

What's your interpretation of these images?
  • Moderate-Large volume ascites – uniformly hypoechoic fluid in upper and lower quadrants
  • Multiple large ovarian follicles
  • Bilateral pleural effusions – hypoechoic. Presence of spine sign
  • And while we don’t have the image for you, there was no significant pericardial effusion

How severe is our patient’s OHSS?

Clearly, from the bedside they are not critically unwell, but biochemically and sonographically they have a high potential for deterioration and complications. The Royal College of Obstetrics and Gynaecology have proposed the following classification for OHSS [3].

So our patient comfortably fits in the “severe” category. Even without a categorical table, this seems clear from our investigations so far. And highlights how you can’t always trust a young, physiologically healthy person who feels well and doesn’t want to be in hospital.

How do we manage our patient?


    • Analgesia: Paracetamol and opiates as required. Avoid NSAIDs due to their renal and obstetric side effects
    • Anti-emetics
    • Avoid nephrotoxins, teratogens, potassium
    • Supplementary O2 if saturations <92%


    • Strict fluid balance chart
    • Drink to thirst +/- IV 0.9% sodium chloride with aim for ~2L fluid intake per day
    • Consider catheterisation if oliguric or crticially unwell
    • If oliguric (<30mL/hr for 4 hours) then commence 4% Albumin +/- uptitrate to 20% Albumin
    • Clexane 40mg daily, and those fashionable clot-preventing TED stockings
    • Consider ascitic drain
    • Refer through to local metropolitan Gynaecology service +/- HDU/ICU

Key Points

    • Always consider OHSS in patients who are undergoing IVF, especially as the presenting symptoms can be so variable
    • Patients can appear remarkably well upon initial assessment despite having moderate to severe OHSS
    • Multi-system involvement is common, be vigilant and perform a thorough systems assessment
    • Supportive treatments are the mainstay of management and patients will often require HDU level monitoring


  1. Kumar P, Sait SF, Sharma A, Kumar M. Ovarian hyperstimulation syndrome. J Hum Reprod Sci. 2011 May;4(2):70-5. doi: 10.4103/0974-1208.86080. PMID: 22065820; PMCID: PMC3205536. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3205536/
  2. South Australian Perinatal Guidelines – Ovarian Hyperstimulation Syndrome – https://www.sahealth.sa.gov.au/wps/wcm/connect/9b61ed004ee5348da663afd150ce4f37/Ovarian+Hyperstimulation+Syndrome_PPG_v3_0.pdf?MOD=AJPERES&amp;CACHEID=ROOTWORKSPACE-9b61ed004ee5348da663afd150ce4f37-nKPnj7D
  3. The management of ovarian hyperstimulation syndrome – The Royal College of Obstetricians & Gynaecologists – https://www.rcog.org.uk/guidance/browse-all-guidance/green-top-guidelines/the-management-of-ovarian-hyperstimulation-syndrome-green-top-guideline-no-5/
Nick Erskine

Nick Erskine

Emergency Registrar

Nick is an Advanced Trainee working at Alfred Hospital. At work he is moderately obsessed with point of care ultrasound and can usually be seen skulking the halls of the department with a Sonosite. Outside of work he lives in fear of needing a FAST himself after coming off his mountain bike on a downhill course too advanced for him. So far he’s always made it to post-ride beers with all his limbs and solid viscera intact, although will never live down the AC joint disruption he sustained when attempting to show off to the Orthopod he was riding with.