LH on GnRH-ant day to basal LH affects the IVF/ICSI outcome of PCOS women undergoing GnRH-antagonist protocol

Objective: The aim of this study was to investigate the influence of ratio of serum luteinizing hormone (LH) on gonadotropin-releasing hormone antagonist (GnRH-ant) day to basal LH (hLH/bLH) on in-vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) outcome in polycystic ovary syndrome (PCOS) women who received GnRH-ant protocol for controlled ovarian hyperstimulation (COH).Methods: This retrospective study was conducted in women with PCOS (n = 1116) who underwent the GnRH-ant protocol for COH between 2015 and 2022 and were stratified as group A (hLH/bLH < 1, n = 489) and group B (hLH/bLH = 1, n = 627) according to the variation of serum LH. The outcomes of COH and the first frozen embryo transfer (FET) cycle were compared between group A, B and the linear relationship between hLH/bLH ratio and IVF/ICSI outcomes were studied by multivariate linear regression analysis and restricted cubic spline (RCS) models.Results: There were significant differences in baseline characteristics and outcomes between group A and B. Group A had higher levels of bLH, AMH, estradiol (E2) on GnRH-ant start day and lower levels of LH on GnRH-ant start day. Group B has better ovulation induction outcomes: more retrieved oocytes, normally fertilized oocytes (2PN), cleavage embryos, available embryos and high-quality blastocysts. Multivariate linear regression analysis found no statistically significant connection between hLH/bLH and clinical outcomes. RCS models showed hLH/bLH had nonlinear association with outcomes, including number of oocytes retrieved, 2PN, available embryos, incidence of OHSS, chemical pregnancy, clinical pregnancy, abortion and live birth.Conclusions: hLH/bLH ratio could be a more forward-looking indicator of clinical outcome in women with PCOS undergoing GnRH-ant protocols than LH on trigger day and the ratio of LH level on trigger day to basal LH. hLH/bLH = 1 may be the best condition for higher live birth rate and lower OHSS rate. LH on GnRH-ant day to basal LH could be an indicator of clinical outcome in women with PCOS undergoing GnRH-ant protocols.