Statistical analyses
SPSS version 24 software (SPSS, Chicago, Illinois, USA) was used for analysis. Descriptive statistical analysis was described as median ± range. Multivariate Poisson regression was used to evaluate the effect of the aforementioned variables with the number of oocytes retrieved. Mann Whitney U test was used to determine a relationship between the variables and their effect on OHSS. The Kruskal Wallis test and Mann Whitney U tests were used to determine significance between age groups and probability of livebirth based upon their age and number of oocytes retrieved. Chi squared testing was utilised to determine statistical significance in those who returned to use their oocytes, to assess between age groups and achievement of livebirth. Statistical significance was set at p<0.05.