title: Ovarian hyperstimulation syndrome: A case control study investigating risk factors.
abstract: BACKGROUND
  Ovarian hyperstimulation syndrome (OHSS) is a complication of in vitro fertilisation (IVF) treatment associated with significant morbidity and mortality.
  
  
  OBJECTIVE
  To assess the severity of OHSS in patients admitted to a tertiary hospital in Melbourne, Australia, and identify risk factors for the condition.
  
  
  METHODS
  The files of patients admitted with OHSS over a five-year period between 2008 and 2013 were reviewed. Baseline characteristics of OHSS patients were compared with IVF patients who did not develop OHSS to establish risk factors for the OHSS patient group. Relative risk was estimated using multivariate Poisson regression. A risk score was then developed using the coefficients from the Poisson regression to aid identification of patients at high risk for the condition.
  
  
  RESULTS
  The following risk factors were associated with an increased risk of developing OHSS: younger age, higher oestradiol (E2) concentration (relative risk (RR) 1.43, P < 0.001), and higher follicle count (RR 1.40, P < 0.001). Lower body mass index (BMI) was not correlated with an increased risk of developing OHSS (RR 1.1, P = 0.19).
  
  
  CONCLUSIONS
  This study demonstrates that a risk score can be calculated from routinely taken measurements to identify patients at high risk of OHSS. Using this risk score could help clinicians reduce the incidence of OHSS by employing preventative strategies in high-risk patients.
authors.affiliation: Monash Medical Centre, Monash Health, Melbourne, Victoria, Australia.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Shields
authors.affiliation: Monash Medical Centre, Monash Health, Melbourne, Victoria, Australia.
authors.forename: Beverley
authors.initials: B
authors.lastname: Vollenhoven
authors.affiliation: School of Health Sciences, University of Tasmania, Launceston, Tasmania, Australia.
authors.forename: Kiran
authors.initials: K
authors.lastname: Ahuja
authors.affiliation: Monash Medical Centre, Monash Health, Melbourne, Victoria, Australia.
authors.forename: Alon
authors.initials: A
authors.lastname: Talmor
mesh_terms: D000328:Adult; D000367:Age Factors; D016022:Case-Control Studies; D004958:Estradiol / Q000097:blood; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects*; D006801:Humans; D006080:Ovarian Follicle; D016471:Ovarian Hyperstimulation Syndrome / Q000209:etiology*; D012372:ROC Curve; D012307:Risk Factors; D012720:Severity of Illness Index
chemical_list: D004958:Estradiol
keywords: artificial reproductive therapy; in vitro fertilisation; ovarian hyperstimulation syndrome