Effectiveness of the antagonist/letrozole protocol for treating poor responders undergoing in vitro fertilization/intracytoplasmic sperm injection: a systematic review and meta-analysis

AbstractIn view of the conflicting data regarding the efficacy of the gonadotropin-releasing hormone (GnRH) antagonist/letrozole (A/L) protocol for treating poor responders undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI), this systematic review and meta-analysis aimed to compare the effectiveness of the A/L protocol and the microdose GnRH agonist flare up (MF) protocol for such treatment. MEDLINE, EMBASE, Web of Science, and the China National Knowledge Infrastructure were searched for studies comparing the A/L and MF protocols for treating poor responders undergoing IVF/ICSI. We retrieved reports of three trials with data for 688 cycles in women. The clinical pregnancy rate was significantly decreased with the A/L compared with MF protocol (RR 0.70; 95% CI: 0.57–0.86; p = 0.001), the duration of gonadotrophin stimulation was lower with the A/L than MF protocol (MD −1.25; 95% CI: −2.37 to −0.12; p = 0.03). Moreover, there was no significant difference in cycle cancellation ra...