P-163 Glucose and lactate dynamics in follicular fluid: strong correlation with oocyte retrieval outcomes and implications for culture media formulations

Abstract Study question How do glucose and lactate levels in follicular fluid correlate with oocyte yield, and what are the implications for optimizing oocyte culture media formulations? Summary answer Glucose increases and lactate decreases with higher oocyte yield; the glucose/lactate ratio strongly correlates with oocyte retrieval, suggesting the need for reconsidering media formulations. What is known already Glucose and lactate are key metabolites in follicular fluid, influencing oocyte maturation and competence. Glucose metabolism in cumulus cells provides energy and reducing equivalents, while lactate supports intracellular pH balance. Variations in culture media compositions, particularly glucose and lactate levels, impact embryo outcomes. Studies highlight the pyruvate dehydrogenase (PDH) complex’s role in glucose metabolism, yet their function as markers of ovarian reserve remains understudied. Limited research has explored follicular fluid glucose and lactate composition and its relevance for reassessing IVF media formulations to better mimic the follicular environment, ultimately optimizing oocyte quality and embryo development. Study design, size, duration This pilot study analyzed Lactate and Glucose concentrations in the follicular fluids from 20 patients, we assessed the formulations of Gx-IVF, Gx-MOPS, and Gx-TL media (Vitrolife), which come into direct contact with oocytes. The study spanned four months. Participants/materials, setting, methods Twenty follicular fluids obtained at time of egg retrieval, metabolites analized using EPOC BGEM BUN test cards, statistical analysis performed to Pearson’s correlation between concentration of the different metabolites, their ratio and number of oocytes retrieved. Main results and the role of chance Lactate levels in follicular fluid decreased with higher oocyte yield, while glucose increased. The glucose/lactate ratio showed a strong inverse correlation with amount of oocytes retrieved (Pearson’s r = -0.77, p < 0.001), suggesting metabolic shifts related to ovarian response. Glucose was below the detection limit for our assay (<20 mg/dL) in Gx-TL and Gx-MOPS, significantly lower than follicular fluid (49.55 mg/dL). Lactate levels were higher in all three media—8.6 mM (Gx-IVF), 9.6 mM (Gx-MOPS), and 8.0 mM (Gx-TL)—compared to follicular fluid (5.07 mM). These findings indicate a metabolic mismatch between follicular fluid and IVF media but larger studies are needed to confirm these results to optimize media formulations. Limitations, reasons for caution This pilot study included a small sample size (20 patients). While correlations were strong, causation cannot be inferred. Follicular fluid composition varies among patients, and external factors may influence metabolite levels. Further studies with larger cohorts are needed to validate findings and assess clinical implications for IVF media formulation. Wider implications of the findings Each patient may have a unique metabolic signature, reflecting their oocytes' specific glucose and lactate needs. Correlating follicular fluid and blood metabolite levels could offer a non-invasive biomarker for predicting ovarian reserve and response, potentially guiding personalized IVF media formulations and improving fertility treatment outcomes. Trial registration number No