Effect of Antagonist Start Day on Cycle Outcomes in Poor Responders

BACKGROUND: Despite the great advances in Assisted Reproductive Technologies (ART), management of poor responders has remained a great challenge. Gonadotropin releasing hormone antagonist (GnRH-ant) has been offered as a patient friendly protocol. In the literature, conflicting data exists about the effect of the GnRH-ant starting day on cycle outcomes. AIM: The aim of this study is to evaluate the effect of GnRH-ant starting day on cycle outcomes of patients with poor ovarian response defined by Bologna criteria. SETTING AND DESIGN: This retrospective cohort study was conducted at an ART clinic of a tertiary hospital. MATERIALS AND METHODS: A total of 361 cycles using flexible GnRH-ant, 195 in Group A (GnRH-ant administered before day 6 of stimulation) and 166 cycles in Group B (GnRH-ant started on or after day 6), were selected retrospectively for the study. STATISTICAL ANALYSIS: Statistical analysis of data was carried out using using IBM SPSS Statistics Software (20.0, SPSS Inc., Chicago, IL, USA). Independent samples t-test and Mann–Whitney U test were used to analyze the variables. RESULTS: Total antral follicle count was significantly higher in Group A compared to Group B (P = 0.009). Duration of stimulation was significantly shorter (P < 0.01) and total dose of gonadotropin used was lower in Group A when compared to Group B (P < 0.01). While higher number of oocytes was retrieved from Group A (P = 0.037), no between-group differences were observed in number of mature oocytes, fertilized oocytes, clinical pregnancy rate or ongoing pregnancy rate (OPR) per embryo transfer (P > 0.05). CONCLUSION: Early GnRH-ant start may point out a favourable response to ovarian stimulation in poor responders. However, clinical or OPRs were not different from the late GnRH-ant start group.