Letrozole and ovarian hyperstimulation syndrome: Retrospective cross-sectional study.

Background: Recently, letrozole has been used to prevent moderate to severe ovarian hyperstimulation syndrome (OHSS) in assisted reproductive technology cycles due to its estrogen-reducing and androgen-increasing effects on the ovaries, affecting granulosa cells, and reducing vascular endothelial growth factor production. Objective: This study aimed to investigate the impact of letrozole consumption in preventing OHSS in infertile women with polycystic ovarian syndrome undergoing in vitro fertilization. Materials and Methods: In this cross-sectional study, among 1743 medical records of infertile women who were scheduled for oocyte retrieval at Research and Clinical Center for Infertility, Yazd, Iran. Data of 343 women with polycystic ovarian syndrome diagnosis and at risk of OHSS was extracted from March 2022-2023. The stimulation was carried out using a flexible gonadotropin releasing hormone (GnRH) antagonist protocol. Women were divided into 2 groups based on whether they received letrozole or not. In the letrozole group, 2.5 mg letrozole twice daily was continued from the trigger day, while in the control group, women did not receive letrozole. The parameters of OHSS severity, hospitalization rates, and the need for albumin prescription were analyzed. Results: 89 women in the letrozole and 254 women in the control group were examined. There was no statistically significant difference between groups in terms of age and body mass index; however, anti-Mullerian hormone was significantly higher than control group (7.53 Conclusion: Recent study indicates that incorporating letrozole into the treatment of GnRH antagonists and cabergoline does not reduce the OHSS severity.