Analysis of clinical outcomes of letrozole combined with GnRH antagonist protocol in in vitro fertilization treatment for patients with poor ovarian response

Objective: This study aimed to evaluate the efficacy of letrozole combined with the antagonist protocol in in vitro fertilization-embryo transfer (IVF-ET) for patients with poor ovarian response (POR). Methods: A total of 176 patients with anticipated POR who underwent IVF at Dongguan Maternal and Child Healthcare Hospital between 2020 and 2024 were enrolled. Based on their preferred stimulation protocol, the patients were divided into two groups: group A ( n = 100), which received the GnRH antagonist protocol alone, and group B ( n = 76), which received letrozole in combination with the antagonist protocol. Baseline characteristics and clinical outcomes were compared between the two groups. Results: The mean total dose of gonadotropins (Gn) required per cycle was significantly lower, and the duration of ovarian stimulation was shorter in group B compared with group A ( P <0.05). Group B also showed significantly higher rates of MII oocytes, available embryos, and high-quality embryos ( P <0.05). There were no significant differences in fertilization rates between the two groups ( P >0.05). Clinical pregnancy and live birth rates were significantly higher in group B ( P <0.05). These findings were further supported by multivariate regression analysis. When group B was sub-divided by age, both pregnancy and live birth rates were significantly lower in the older age group (39–42 years) compared to the younger age group (35–38 years). Conclusion: The combination of letrozole with a GnRH antagonist protocol in patients with expected POR (Patient-Oriented Strategies Encompassing Individualized Oocyte Number groups 3 and 4) reduced the mean total Gn dosage and shortened the stimulation duration. It also increased the number of oocytes retrieved and available embryos, and improved oocyte and embryo quality, thereby enhancing pregnancy outcomes. This effect was more pronounced in younger patients with POR.