Antioxidant status of human follicular fluid: natural versus controlled ovarian hyper-stimulated cycles

Controlled ovarian hyperstimulation (COH) is used in standard protocols in in vitro fertilization (IVF). However, its use is associated with clinical complications such as ovarian hyperstimulation syndrome. The evidence indicates that the natural cycle (NC) has a lower risk and is more physiological. In this study, we have determined the antioxidant status of follicular fluid at the time of oocyte retrieval following NC or COH. Forty-one fertile women (oocyte donors) followed both cycles. In NC no exogenous gonadotrophins were used, and only hCG was given to induce ovulation. We determined TAA, ORAC, - and tocopherol, nitric oxide, and the activities of SOD, catalase, total and Se-dependent glutathione peroxidases, and paraoxonases. Results showed that TAA, -tocopherol, and the paraoxonase, arylesterase, and simvastatinase activities were significantly higher in NC, compared with COH. Our results indicate that NC is associated with higher follicle antioxidant protection and provide important insights into prevention of hyperstimulation side effects.