Does controlled ovarian stimulation during in vitro fertilization affect the level of nitric oxide a potential indicator of oocyte quality?

Infertility is a major global health issue, affecting approximately 9% of couples worldwide. Its prevalence increased steadily over the preceding decades, paralleling environmental and lifestyle changes. One assisted reproductive technique to overcome infertility is in vitro fertilization (IVF). The IVF procedure consists of several stages, one of which is controlled ovarian stimulation (COS) via various protocols allowing follicular recruitment and maturation in preparation for oocyte retrieval. Follicular fluid (FF) is the microenvironment in which oocytes develop during folliculogenesis, and FF information could be used to assess follicle and oocyte development and maturation stages. Nitric oxide (NO) is a component of FF that is being studied as a predictive factor of follicle maturation and egg quality and as a potential indicator of the success of COS during the IVF process. The hypothesis was that COS affects NO levels in the serum; more specifically, that NO levels in serum after COS correlate with NO levels in FF, based on literature data on the influence of female reproductive hormones on NO metabolism and data on the change in the hormonal milieu affected by COS use.