Protocol shift from agonist to antagonist or vice versa after an unsuccessful intracytoplasmic sperm injection cycle on the same patient does not improve outcome

Objective: While there's a growing data on the comparison of GnRH agonist and GnRH antagonist protocols, no clear study exists on the effects of both protocols on the same patient. The aim of the present study was to compare the success rates of protocol shift and proceeding with the same protocol after an unsuccessful intracytoplasmic sperm injection (ICSI) cycle. Materials and Methods: Three hundred and forty-five normal responder patients who had a previously failed ICSI cycle between January 2011 and December 2015 were reviewed. The study (n = 73) and control (n = 93) groups in the first cohort were composed of patients whose protocol were shifted to antagonist and who proceeded with agonist. The study (n = 33) and control (n = 146) groups in the second cohort were composed of patients whose protocol were shifted to agonist and who proceeded with antagonist. Results: Total dose of gonadotropins, maximum estradiol levels, and number of oocytes collected were significantly higher in agonist protocol than in antagonist protocol (P = 0.021, P = 0.013, and P = 0.003, respectively). Cycle cancellation rates were significantly lower in agonist protocol than antagonist protocol (P = 0.005). The pregnancy rates in patients who shifted to antagonist and proceeded with agonist were 57.8% and 50.8%, respectively (P = 0.399). The pregnancy rates in patients who shifted to agonist and proceeded with antagonist were 33.3% and 47.9%, respectively (P = 0.202). Conclusion: Protocol shift following a failed ICSI cycle with either agonist or antagonist protocol does not affect outcome.