Background: Nitric oxide (NO) is an important modulator of ovarian physiology, which contributes to angiogenesis, steroidogenesis, and redox control. The stable metabolites nitrate (NO₃⁻) and nitrite (NO₂⁻) may indicate real-time follicular function during IVF. Methods: In this prospective study, we included 89 women who underwent controlled ovarian stimulation. The Griess test was used to measure NO₂-NO₃ concentrations in follicular fluid collected on the day of oocyte retrieval. Non-parametric and correlation tests were used to investigate the associations between oocyte yield, maturity (MII), fertilization (2PN), embryo development, and hormone levels. Results: Higher NO₂-NO₃ levels were substantially associated with increased total oocyte count, MII oocytes (p = 0.014), and 2PN embryos (p = 0.029). This suggests a strong relationship between NO bioavailability and oocyte competence. NO₂-NO₃ levels showed a positive correlation with estradiol (p < 0.001) and progesterone (p < 0.001), suggesting a possible function in granulosa cell steroidogenesis. Conclusions: Follicular NO metabolites are candidate functional indicators for oocyte quality evaluation and intrafollicular steroidogenic activity. Their predictive value may improve customized IVF treatment, especially in individuals with complicated ovarian phenotypes such as PCOS or decreased ovarian reserve.

Background: This case–control study investigates whether miR-27a rs895819 A>G polymorphism is associated with an increased risk of recurrent pregnancy loss (RPL) in Caucasian Greek women. Methods: This study included 93 women with at least two unexplained miscarriages before the 24th week of gestation (RPL group) and 107 women with no pregnancy loss history (control group). The miR-27a rs895819 A>G polymorphism was detected using PCR amplification, followed by DraIII-HF restriction enzyme digestion. Results: The GG genotype was linked to a significantly higher risk of RPL (p-value = 0.00005), whereas the AA genotype was associated with a significantly lower risk (p-value = 0.00036). The AG genotype appeared more frequently in women with RPL (49.5% vs. 44.9% in controls), but the difference was not statistically significant (p-value = 0.5139). Conclusions: To our knowledge, this is the first study demonstrating that the miR-27a A>G polymorphism was significantly associated with a higher risk of recurrent miscarriage in Caucasian women. These findings provide evidence that the GG genotype may serve as a potential genetic marker for identifying women at higher risk of recurrent miscarriage, offering valuable insights for genetic counseling and reproductive medicine.

In vitro fertilisation (IVF) has significant hurdles due to individual differences in ovarian response during controlled ovarian stimulation. The Asn680Ser polymorphism of the follicle-stimulating hormone receptor (FSHR) is linked to varying ovarian sensitivity to FSH. However, its relationship with intrafollicular redox signalling remains unclear. Nitric oxide (NO) is a crucial compound that functions inside follicles and participates in angiogenesis, steroidogenesis, and oocyte competence. This prospective observational research classified women undergoing IVF into Asn allele carriers (Asn/Asn and Asn/Ser) and Ser/Ser homozygotes, according to the FSHR Asn680Ser polymorphism. The groups were assessed according to follicular fluid nitric oxide metabolites (NO₂-NO₃), fertilisation results, ovarian response indicators, and hormonal profiles. No substantial variation was seen between baseline and trigger-day hormone levels. In contrast, Ser/Ser individuals had a significantly higher total count of recovered oocytes, an elevated number of metaphase II oocytes, and enhanced fertilisation outcomes relative to carriers. The Ser/Ser group demonstrated increased intrafollicular NO₂-NO₃ concentrations. This difference was not statistically significant. These results link FSH receptor genetics to functional follicular competence, indicating that the FSHR Asn680Ser polymorphism is associated with differing ovarian responsiveness during IVF and may affect intrafollicular nitric oxide bioavailability.