New device for sperm preparation involving migration-gravity sedimentation without centrifugation compared with density-gradient centrifugation for normozoospermic intrauterine insemination

OBJECTIVE: To investigate the efficacy of a new device for sperm preparation involving migration-gravity sedimentation without centrifugation (MIGLIS), compared with density-gradient centrifugation (DGC) for normozoospermic intrauterine insemination (IUI). DESIGN: Retrospective cohort study. SETTING: Not applicable. PATIENTS: A total of 10,318 cases of IUI (3,015 MIGLIS and 7,303 DGC) between October 2013 and September 2019. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Sperm analysis, subsequent pregnancy outcomes, and complications. RESULTS: MIGLIS was associated with a lower sperm recovery rate and fewer injected sperm compared with DGC. However, the overall pregnancy rates following MIGLIS and DGC were similar (MIGLIS 8.8%, DGC 9.3%). In a subanalysis according to age, the pregnancy rate was higher for MIGLIS among women 40–41 years of age (8.6% vs. 5.9%). Peritonitis was the only recorded complication, with similar frequencies in the MIGLIS and DGC groups (MIGLIS two cases, DGC four cases). No cases became severe, and all improved after antibiotic treatment. There were no cases of uterine cramping or pain symptoms. CONCLUSIONS: MIGLIS is a new sperm preparation method that does not require centrifugation. Its use was associated with pregnancy rates similar to those with DGC and a higher pregnancy rate in older women. MIGLIS is a novel sperm preparation method for selecting spermatozoa with high motility and good fertilization ability in patients undergoing IUI, in vitro fertilization, and intracytoplasmic sperm injection.