A novel GnRH antagonist protocol based on LH levels versus traditional flexible GnRH antagonist protocol in PCOS patients undergoing in vitro fertilization: study protocol for a randomized controlled, non-inferiority trial

BACKGROUND: The gonadotropin-releasing hormone (GnRH) antagonist protocol is advantageous given that it can avoid severe ovarian hyperstimulation syndrome (OHSS), especially for patients with polycystic ovary syndrome (PCOS). Basic and clinical evidence has shown that a threshold of luteinizing hormone (LH) stimulation is required for adequate follicular development and oocyte maturation. Ultra-low or high levels of LH are detrimental to pregnancy outcomes. We previously demonstrated that LH could be an indicator for the timing and dosage of antagonist administration in a retrospective study. METHODS/DESIGN: In this randomized, single-center, non-inferiority trial, we aim to test the hypothesis that there is no significant difference in cumulative ongoing pregnancy rates between PCOS patients stimulated with LH-based flexible protocol versus traditional flexible GnRH antagonist protocol. The primary efficacy endpoint will be the cumulative ongoing pregnancy rate per cycle. The secondary outcomes will be clinical pregnancy rate, cancelation rate, serious OHSS rate, and cost-efficiency. The cumulative ongoing pregnancy rate per cycle in PCOS women was 80%. Considering that a non-inferiority threshold should retain 80% of the clinical effect of a control treatment, a minimal clinical difference of 16% (two-sided: α, 2.5%; β, 20%) and a total of 196 patients were needed. Anticipating a 10% dropout rate, the total number of patients required was 216. DISCUSSION: The results of this study will provide evidence for the efficacy and safety of the LH-based flexible GnRH antagonist protocol in PCOS patients. Moreover, it evaluates the cost-efficiency of both protocols. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR1800018129. Date assigned: 31 August 2018. Protocol version: 1.0 (18 July 2017) SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-022-06586-1.