How frequent is severe ovarian hyperstimulation syndrome after GnRH agonist triggering in high-risk women? A systematic review and meta-analysis

•Although the incidence of severe OHSS after GnRH agonist triggering of final oocyte maturation in high risk women was low in all strategies examined, its elimination (upper 95% CI=0) was only present in studies where no form of luteal phase support was added.•The current study, sets the discussion about the best method to manage high risk women for OHSS undergoing ovarian stimulation for IVF on a new basis, since it shows that it is possible to eliminate sever OHSS. Apparently, if safety of an ART procedure, regarding severe OHSS incidence, is compromised, this represents a rate-limiting step in offering such a treatment, if an alternative method that will not lead to severe OHSS is present. The aim of the present systematic review and meta-analysis was to assess the incidence of severe ovarian hyperstimulation syndrome (OHSS) after triggering of final oocyte maturation with gonadotrophin releasing hormone agonist (GnRHa) in high-risk women. The pooled incidence of severe OHSS in high-risk women who did not receive any form of luteal phase support was 0% (95% CI 0.0 to 0.0, I2 = 0%, random-effects model, 14 data sets, 983 women). The pooled incidence of severe OHSS in high-risk women in whom HCG was added to standard luteal phase support was 1% (95% CI 0.0 to 2.0, I2 = 27.02%, random-effects model, 10 data sets, 707 women). The incidence of severe OHSS in high-risk women triggered by a combination of GnRHa and HCG (dual triggering), who received standard luteal phase support, was 1% (95% CI 0.0 to 3.0, one study, 182 women). The incidence of severe OHSS in high-risk women, is not eliminated when HCG is administered either concomitantly with GnRHa (dual triggering), during the luteal phase after GnRHa triggering, or both. On the contrary, it is eliminated when no luteal support is administered.