Follicular Sensitivity Index: A Tool To Predict Successful Conception After Intra-cytoplasmic Sperm Injection

Follicular sensitivity index (FSI) is used for estimation of follicular responsiveness to controlled ovarian hyperstimulation (COH) during intra-cytoplasmic sperm injection (ICSI). In a retrospective study, FSI of 1,385 females was calculated as [pre-ovulatory follicle count (PFC) × 100,000]/ [antral follicle count (AFC) × total received stimulation doses]. Females were then categorised into low, middle and high FSI groups according to FSI tertile values. FSI was 8.65 ±2.82 in non-pregnant as compared to 12.02 ±2.04 (p <0.01) in pregnant cohort. FSI turned out to be a strong predictor of successful conception on the receiver operating curve with cutoff value 10.36 at 76% specificity, sensitivity of 86% and area under the curve (AUC; 0.83). Calculation of FSI can thus predict the chances of successful conception in females with different causes of infertility. Key Words: Follicular sensitivity index, Infertility, Intra-cytoplasmic sperm injection, Ovarian response, Follicular output rate.