Evaluation of the follicular fluid thiol/disulfide balance among patients with poor ovarian response.

Objective: This study aimed to compare the thiol/disulfide balance, myeloperoxidase, and ischemia-modified albumin levels in the follicular fluid (FF) of poor ovarian response (POR) and normal ovarian response (NOR) women who received intracytoplasmic sperm injection (ICSI).

Methods: The study was performed between March 2021 and April 2022 at the Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Ankara City Hospital. The study included 27 POR and 35 NOR women who underwent ICSI. FF was obtained after the controlled ovarian stimulation cycle. The FF thiol/disulfide balance was detected using spectrophotometric methods. A correlation analysis was conducted to determine whether these oxidative stress markers could contribute to predicting oocyte quality.

Results: Disulfide levels were significantly higher in the NOR group than in the POR group (p=0.014). The number of fertilized egg (2PN) oocytes was positively correlated with the total thiol level (r=0.258, p=0.046). The disulfide level was positively correlated with the anti-Müllerian hormone level (r=0.262, p=0.039) and the total number of retrieved oocytes (r=0.335, p=0.008).

Conclusion: The disulfide levels differed significantly between the NOR and POR groups. The statistically significant differences of fewer metaphase II oocytes and lower percentage of good-quality embryos in the NOR group compared to the POR group might have resulted from the NOR group's elevated disulfide levels. The total thiol levels correlated with the total of 2PN oocytes. Future studies should examine the thiol/disulfide balance at assisted reproductive technology centers to predict which oocytes could be fertilized.