Symposium: Update on prediction and management of OHSS. Optimal dose of HCG for final oocyte maturation in IVF cycles: absence of evidence?

There is an ongoing debate over the optimal dose of urinary HCG (u-HCG) that can trigger final oocyte maturation, leading to higher IVF success rate without increasing the risk of ovarian hyperstimulation syndrome (OHSS). A systematic review was conducted of all studies that compared the effect of at least two doses of u-HCG for final oocyte maturation on IVF outcomes and on the incidence of OHSS. The primary outcome was the live birth rate, and the secondary end-points were the number of oocytes retrieved, fertilization, implantation and pregnancy rates, and the incidence of OHSS. Only two amongst the six included studies were randomized controlled trials (RCT). Meta-analytic pool was not feasible due to insufficient number of studies assessing the same outcome and significant heterogeneity. The majority of studies concluded that the clinical outcomes were similar between women receiving 5000 or 10,000 IU of u-HCG. The incidence of OHSS was not reduced in the high-risk population even with lower dose of u-HCG. Until large scale RCT addressing the clinical effectiveness and the adverse outcomes related to various doses of u-HCG are conducted, the dose of u-HCG for final oocyte maturation for women referred for IVF needs to be individualized.