Pituitary suppression protocol among Bologna poor responders undergoing ovarian stimulation using corifollitropin alfa: does it play any role?

RESEARCH QUESTION: Does the type of pituitary suppression protocol influence cumulative live birth rate (LBR) in Bologna poor responders treated with corifollitropin alfa (CFA)? DESIGN: Retrospective cohort analysis including poor responder patients fulfilling the Bologna criteria who underwent their first intracytoplasmic sperm injection cycle using a CFA-based ovarian stimulation protocol between 2011 and 2017. The starting dose of CFA was 150 µg. The primary outcome was cumulative LBR, defined as the first delivery of a live born resulting from the fresh and all the subsequent frozen embryo transfers. RESULTS: A total of 717 cycles were divided into three groups: A (gonadotrophin-releasing hormone [GnRH] antagonist protocol, n = 407), B (long GnRH agonist protocol, n = 224) and C (short GnRH agonist protocol, n = 86). Cumulative LBR did not significantly differ between groups (20.1% versus 17.4% versus 14.0%; P = 0.35). Significantly more patients in Group A had supernumerary embryos cryopreserved (28.3% versus 18.4% versus 11.6%; P < 0.001). Days of additional highly purified human menopausal gonadotrophin 300 IU injections following CFA were significantly different between Groups A, B and C (3 versus 5 versus 3 days; P < 0.001). Multivariate logistic regression analysis showed that the number of oocytes retrieved remained an independent predictive factor (odds ratio 1.23, 95% confidence interval 1.16-1.31) for cumulative LBR. CONCLUSIONS: Poor responders according to the Bologna criteria in whom CFA is used for ovarian stimulation had comparable cumulative LBR, irrespective of the type of pituitary suppression. An increase in number of oocytes retrieved is an independent variable related to cumulative LBR.