GNRH1 and ovarian hyperstimulation syndrome: One reason for monitoring is early prediction of ovarian hyperstimulation syndrome (OHSS), a potential life-threatening complication of ovarian stimulation with gonadotropin receptor hormone (GnRH)-agonists, which can lead to haemoconcentration, coagulopathy, pleural and pericardial effusion and hepatorenal failure (Devroey et al., 2011).