{Reference Type}: Comparative Study {Title}: Gonadotrophin-releasing hormone agonist protocol of controlled ovarian hyperstimulation as an efficient treatment in Bologna-defined poor ovarian responders. {Author}: Stimpfel M;Vrtačnik-Bokal E;Pozlep B;Kmecl J;Virant-Klun I; {Journal}: Syst Biol Reprod Med {Volume}: 62 {Issue}: 4 {Year}: Aug 2016 {Factor}: 2.958 {DOI}: 10.3109/19396368.2016.1170229 {Abstract}: In this retrospective study the outcomes of two protocols of controlled ovarian hyperstimulation and natural cycle in poor ovarian responders defined according to the Bologna criteria were compared to elucidate which approach is more suitable for the treatment of these patients. We comparatively analyzed 142 cycles of GnRH antagonist (GnRH-ant) protocol, 53 cycles of GnRH agonist (GnRH-a) protocol, and 36 natural cycles. The mean number of oocytes (2.8±1.8) and embryos (1.6±1.2) per aspiration was significantly higher in GnRH-a protocol in comparison to GnRH-ant protocol and natural cycle, but the proportion of immature, fertilized oocytes, and embryos, including the quality of transferred embryos, was very similar in all treatments. The proportion of pregnancies per oocyte aspiration did not differ significantly between treatments (18.9% after GnRH-a, 10.6% after GnRH-ant, 5.6% after natural cycle), but the live birth rate per aspiration was significantly higher after GnRH-a protocol than after GnRH-ant protocol (15.1% vs. 4.2%; p=0.024).