Materials and Methods: This study was a cohort study of women with infertility who had a history of two consequent IVF cycles due to an unsuccessful previous attempt and were recruited between 2016 and 2019. The patients were treated with either an agonist or antagonist protocol in the first or second round. They were categorized into two groups based on whether the second round was the same as the first one or different. The primary outcomes included the number of M2 oocytes, the number of transferred embryos, the chemical pregnancy rate, and the clinical pregnancy rate. The secondary outcome was the live birth rate. Statistical analyses were performed using SPSS version 26 software.

Results: A total of 39 women and 78 cycles with a history of infertility, with a mean age of 29.72 (5.36, SD), were evaluated in two groups: same (17, 43.6%) and different (22, 56.4%) protocols. Primary infertility was the most frequent type of infertility, recorded in 31 (79.6%) individuals. No significant differences were found between the two groups in terms of mean endometrial diameter (P = 0.820), HCG administration (P = 0.069), mean stimulation duration (P = 0.931), mean total dose of administered gonadotropins (P > 0.05), and embryo transfer types (P = 0.051). Also, no significant differences were found in the primary outcomes between the same and different protocol groups (P > 0.05). The live birth rate also showed no significant difference as a secondary outcome (P = 0.954).

Conclusions: This study found no significant difference in IVF outcomes when switching between GnRH agonist and antagonist protocols or using the same protocol for consecutive rounds.