Evaluation of Follicular Oocyte Index (FOI) as a Predictive Marker in Association with Female Age for Clinical Pregnancy Rate in IVF Cycles

Abstract

Objective: To evaluate the Follicular Oocyte Index (FOI) as a dynamic marker of ovarian responsiveness and its predictive value for clinical pregnancy, particularly in association with female age, in patients undergoing IVF cycles. Methods: This prospective cohort study included 114 women undergoing IVF cycles at a tertiary care fertility center. FOI was calculated as the ratio of oocytes retrieved to antral follicle count (AFC) and categorized into four ranges (<40%, 40–60%, 61– 80%, >80%). Statistical analyses included correlation, regression, and ROC curve validation to assess FOI's predictive value. Results: FOI showed a strong positive correlation with beta-HCG positivity (r = 0.72) and clinical pregnancy rate (r = 0.67, p < 0.001). FOI values declined with age: patients aged 20–30 years had the highest mean FOI (78.4%), while those aged 41– 45 had the lowest (43.5%). Logistic regression confirmed FOI as an independent predictor of clinical pregnancy (OR = 2.57). Patients with FOI >80% achieved a 73.8% pregnancy rate versus 27.6% in those with FOI <40%. Conclusion: FOI is a robust, independent predictor of clinical pregnancy in IVF. Its integration with age and other markers enhances IVF planning, allowing personalized treatment strategies.