Microfluidic sperm separation for intracytoplasmic sperm injection yields similar blastocyst rates compared with density gradient, however, may be of benefit for male factor infertility: a randomized sibling oocyte study

Objective To study whether microfluidic sperm separation in intracytoplasmic sperm injection cycles provides any benefit over density gradient sperm separation for good-quality embryo formation. Design Randomized sibling oocyte study. Subjects Patients undergoing intracytoplasmic sperm injection. Intervention Microfluidic sperm separation vs. density gradient sperm separation Main Outcome Measures Primary outcomes were percentage of good-quality blastocyst formation. Secondary outcomes included sperm parameters after sperm separation, including percent motility, grade of forward progression, fertilization rates, blastocyst formation rates, and ploidy rates in the event that preimplantation testing for aneuploidy was performed. Additionally, subanalysis on those with male factor infertility was performed, evaluating primary and secondary outcomes above. Results A total of 34 cycles enrolled into the study, yielding 456 oocytes, 231 randomized to microfluidics and 225 to density gradient (DG). Average microfluidic fertilization rate was 76.1% ± 19.2% and 72.4% ± 26.6% for DG. Microfluidic blastocyst formation rate was 58.4% ± 31.9% compared with 58.7% ± 30.5% for DG. Good-quality blastocyst formation rate for microfluidics was 51.4% ± 29.7% and for DG was 51.7% ± 30.9%. Euploid rates were 43.8% ± 35.5% in the microfluidics cohort and 33.7% ± 33.3% in the DG cohort. Subanalysis of cycles with male factor infertility revealed good-quality blastocyst formation rate was 45.9% ± 30.9% after microfluidics and 55.1% ± 29.2% for DG. Subanalysis of cycles with male factor infertility revealed an euploid rate of 50.0% ± 37.6% after microfluidics compared with 18.4% ± 24.5% for DG. Conclusion There were similar rates of good-quality embryo formation after intracytoplasmic sperm injection using sperm separated with microfluidics compared with density gradient; however, subanalysis of the male factor infertility group revealed higher euploid rates with microfluidics. Trial Registration This trial was registered in clinicaltrials.gov, ID number NCT04818593. URL: https://clinicaltrials.gov/study/NCT04818593. Date of registration: 3/25/2021. Date of first enrollment: 6/18/2021.