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

Abstract 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.