P-073 Comparison of human preimplantation embryo development after sperm selection for ICSI using the microfluidic ZyMōt device versus density gradient centrifugation
Authors: Balakaier H , Kuznyetsova I , Chaudary A , Librach C 
Published: June 2023

Study question

Does microfluidic sperm selection using ZyMōt device has a significant effect on blastocyst development, ploidy, and improves pregnancy outcomes when compared with density-gradient centrifugation.

Summary answer

The study demonstrated that sperm selection using a microfluidic device had no impact on euploid blastocyst rates or clinical pregnancy outcomes.

What is known already

Selecting competent spermatozoa with the highest genomic integrity for ICSI is a key to achieving normal embryo development and a healthy live birth. Several sperm preparation techniques have long been scrutinized with varied success. The novel microfluidic ZyMōt device appears promising for improving the quality of sperm used in Assisted Reproductive Technologies. Preliminary tests have shown that ZyMōt may increase sperm motility and considerably decrease DNA fragmentation, which could potentially enhance euploid blastocyst development rates. However, the impact of this sperm selection method on clinical outcomes has not been fully investigated.

Study design, size, duration

This is a retrospective cohort study performed in a single academic IVF centre (IRB # 16367). Data were collected from 1286 ICSI cycles in 2020-2021 (730 with ZyMōt and 556 with DGC), including 867 cycles with PGT-A outcomes. Morphological grading of 6640 blastocysts cultured in a time lapse imaging incubator (Embryoscope™) and ploidy of 4783 blastocysts using high resolution NGS (Illumina platform and Blue Gnome) were compared between the two study groups.

Participants/materials, setting, methods

All male partners were normo-spermic according to standard semen analysis. ICSI results for a total of 7277 mature oocytes injected with spermatozoa processed with ZyMōt device and 5977 oocytes injected with spermatozoa processed by gradient-density centrifugation were compared. For the analysis of 1478 euploid embryo transfer outcomes, all cases included a single blastocyst transferred in a frozen-thaw cycle. Associated patient characteristics, including age and fertility diagnosis were collected.

Main results and the role of chance

A significantly higher fertilization rate was observed with ZyMōt compared to the gradient prepared sperm (83.4% vs 81.0%, P = 0.0004, respectively). The blastocyst rates (61.3%, vs 60.4%, P = 0.34) as well as the proportion of high-quality blastocysts were similar in both groups (P = 0.20). Euploidy rates were not different between all female age groups, including young egg donors (≤ 30y of age) to patients with advanced maternal age (&gt;40 y of age). Microfluidic sperm selection did not improve clinical pregnancy rates after euploid embryo transfer (42.9% vs 41.4%; P = 0.58).

Limitations, reasons for caution

Although this is the largest study to date evaluating application of the ZyMōt device, the retrospective nature and cohort design limited the interpretation of our results. The patient population did not include male factor cases and sperm DFI data was not available. Embryo transfer outcomes were limited to clinical pregnancies.

Wider implications of the findings

The ZyMōt device offers a convenient alternative to standard sperm processing by density gradient method. Further studies are needed to fully determined the impact of ZyMōt on embryo quality and clinical outcomes in different age and diagnosis groups of patients; particularly for those with high DFI and poor IVF/ICSI outcomes.

Trial registration number

not applicable