Effect of a premature luteinizing hormone surge on cumulative live birth rate during a flexible GnRH antagonist protocol: a retrospective study

Abstract Background: A premature luteinizing hormone (LH) surge refers to an endogenous LH peak that occurs before follicle maturation or human chorionic gonadotropin injection in the process of controlled ovarian hyperstimulation. Previous studies demonstrated that a premature LH surge was associated with a decline in clinical pregnancy rates in fresh embryo transfer cycles. No studies have reported the effect of a premature LH surge on the cumulative pregnancy rate (CPR) and cumulative live birth rate (CLBR). The aim of this study was to explore the effect of a premature LH surge on the CPR and CLBR of patients during a flexible GnRH antagonist protocol.Methods: A total of 428 infertile women undergoing IVF/ICSI were recruited for this retrospective study. Only women who either delivered a live infant or had no remaining frozen embryos after a single stimulation cycle were included in the analysis. During the study period, each patient underwent a flexible GnRH antagonist protocol. Women were divided into two groups according to the presence (Group A) or absence (Group B) of a premature LH surge. The primary outcome measures were the CPR and CLBR per ovarian stimulation cycle. The secondary outcome measures were the number of oocytes retrieved, fertilization rate, clinical pregnancy rate, and implantation rate.Results: Fifty-one women (11.92%) experienced a premature LH surge (Group A), and the other 377 (88.08%) women were assigned to Group B. There was no significant difference between Group A and Group B in the clinical pregnancy rate or live birth rate in the fresh embryo transfer cycle. The primary outcome measures, the CPR and CLBR per ovarian stimulation cycle, were not significantly different between the premature LH surge group and the control group. According to the analysis stratified by ovarian response (normal or high), there were no significant differences in pregnancy outcomes between the groups with and without a premature LH surge.Conclusions: Our study demonstrated that a transient premature LH surge without progesterone elevation had no adverse effect on the CLBR of patients on a flexible GnRH antagonist protocol. Therefore, a transient LH surge should not be an indicator for cycle cancellation.