ABSTRACT
BACKGROUND: Unexplained infertility is defined as the absence of any pathology in the basic evaluation performed in couples who cannot achieve pregnancy after 1 year of unprotected sexual intercourse. The results of tests examining the causes of infertility show no identifiable cause in almost 15% of couples. AIM: The aim of this study was to investigate the effects of reactive oxygen species (ROS) on pregnancy and embryos. METHODS: This study included 200 patients, aged between 20-44 years, with unexplained infertility, who had recurrent intrauterine inseminations failures and hence started in vitro fertilization (IVF)/intracytoplasmic sperm injection treatment. Some amounts of waste follicular fluid samples were collected by embryologists from the oocytes of these patients during the ovum pick-up procedure. Next, total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) values were calculated in the biochemistry laboratory. RESULTS: In terms of pregnancy status, both follicular TOS and OSI values were not significantly different in patients with biochemical and clinical pregnancy, whereas TAS values were significantly higher in patients with pregnancy (P < 0.05). In terms of embryo quality, no significant difference was observed in TAS, TOS, and OSI values between grade 1 and 2 embryos, whereas pregnancy rates were significantly higher in patients who received grade 1 embryo transfer (P < 0.05). However, the follicular fluid TAS levels were significantly lower in smoking patients than in those who did not smoke; TOS and OSI levels were significantly higher. CONCLUSION: This study showed that exposure to oxidative stress might be a causative factor for infertility. In addition, ROS decreased the level of TAS by increasing OSI in the follicular fluid; thus, antioxidant supplementation might be a necessity.