Comparative Efficacy of Microfluidics and Density Gradient Centrifugation for Sperm Preparation in IVF: A Randomized Controlled Trial

Abstract

OBJECTIVE: To compare the effectiveness of microfluidic sperm sorting (MC) and traditional density gradient centrifugation (DGC) in reducing sperm DNA fragmentation index (DFI) and evaluate their impact on clinical outcomes in IVF cycles. METHODS: In this randomized controlled trial, 119 couples undergoing IVF were allocated to either the MC or DGC group. Sperm DNA fragmentation was assessed before and after preparation. Primary outcomes included live birth rate and DFI reduction. Secondary outcomes were sperm quality parameters, fertilization rate, embryo development, and pregnancy outcomes. Subgroup analysis was conducted based on initial DFI levels (<15% vs. ≥15%). RESULTS: The MC group demonstrated significantly greater and more consistent DFI reduction, particularly in samples with high baseline DFI (≥15%), compared to the DGC group. Although the number of oocytes retrieved was higher in the MC group, no significant differences were observed between groups in fertilization rate, Day-2 embryo quality, clinical pregnancy, ongoing pregnancy, or live birth rates. Subgroup analysis also showed no significant differences in outcomes based on baseline DFI levels. CONCLUSIONS: Microfluidics is an effective method for reducing sperm DNA fragmentation, particularly in samples with high DFI. However, this improvement does not necessarily guarantee better clinical outcomes in IVF. Baseline sperm DNA fragmentation index (DFI) may still act as an independent prognostic factor influencing IVF success, regardless of the sperm preparation method used.