Received December 14, 2016
Accepted March 29, 2017

Objective: The aim of this study was to evaluate the efficacy of a not expensive, easy and fast technique (direct micro swim-up) for sperm preparation in intracytoplasmic sperm injection (ICSI) treatments without the use of centrifuge. Methods: We conducted a multicentre study in which a total of 140 ICSI-cycles were included. Sibling oocytes were divided into two groups according to semen preparation procedures: group A, discontinuous gradients (DG) (oocytes n=668), and group B, direct micro swim-up (MSU) (oocytes n=660). Differences in some key performance indicators were analyzed. Results: Fertilization rates were not statistically different between DG and MSU groups (76.0% vs. 81.8%, respectively, p=0.248); while significant differences were found as regards blastulation rate per fertilized oocytes (41.7% vs 58.5%, p=0.009), blastulation rate per D3 embryos (46.1% vs 63.7%, p=0.045), and pregnancy rate (25.8% vs. 41.9%, p=0.045). The abortion rate was reduced in the MSU group as compared to DG, but not in a significant manner (12.9% vs. 29.4%, p=0.161). Conclusion: The MSU procedure has the advantage of reducing costs, time and mismatches, while ensuring comparable and in some cases better results than DG treatments. This technique can therefore be used as an alternative method to other conventional semen treatments.