P-106 A novel sperm selection technique to select the most motile spermatozoa with superior genomic integrity for intrauterine insemination
Authors: Chan J , Kocur O , Xie P , De Jesus A , Ng L 
Published: July 2024

Abstract

Study question
Does the utilization of a novel sperm selection method via microfluidics(MFSS) confer advantages over the conventional density gradient(DG) technique for couples undergoing intrauterine insemination(IUI)?

Summary answer
MFSS efficiently selected spermatozoa with increased motility and genomic integrity in an expedited manner, leading to an enhanced IUI clinical outcome.

What is known already
The first-line reproductive treatments for infertile couples are timed intercourse and IUI. In IUI, DG is commonly utilized to isolate motile spermatozoa. However, this method requires technical skills and processing time. Furthermore, DG exposes spermatozoa to silica gel particles and reactive oxygen species during centrifugation. MFSS represents a safer and more efficient sperm processing method to minimize human intervention. It has been reported by several investigators that MFSS selects spermatozoa with higher progressive motility and lower DNA fragmentation in ART. We have decided to investigate the efficacy of MFSS as an alternative method to select spermatozoa for IUI.

Study design, size, duration
Since 2017, post-processing semen parameters and Sperm Chromatin Fragmentation (SCF) was measured in the raw, DG-, and MFSS-processed specimens. Clinical outcomes were compared between IUI cycles using DG versus MFSS processing. Paired analyses were performed on patients who underwent history IUI-DG and subsequent IUI-MFSS, and cycles were split into natural (NC) or clomid or letrozole superovulation (CLO) cohorts.

Participants/materials, setting, methods
A total of 855 couples underwent 922 IUI-MFSS. Post-processing semen parameters and clinical outcomes were compared with those of 2325 age-matched couples who underwent 8322 IUI-DG during the same period. All male partners included in this study had normal semen parameters. DG was performed according to WHO, while MFSS as per manufacturer protocol(ZyMōt® Multi 850µL). SCF was assessed by TUNEL(normal threshold,≤15%). For all comparisons, +bHCG and clinical pregnancy(CPR,+FHB) were compared.

Main results and the role of chance
IUI-DG(maternal age:32.7±2;paternal age:37.9±6) resulted in a final concentration of 48.4±33x106/mL and motility of 88.1±4%. IUI-MFSS resulted in a decrease in a final concentration at 36.4±17x106/mL with a remarkable increase in motility at 98.6±1%(P&lt;0.01). SCF was 6.0±4% in raw specimen, became 4.7±2% after DG, and 2.5±2% after MFSS(P&lt;0.01).
Overall, IUI-DG(n = 2325) resulted in a +bHCG of 12.7%(1065/8322) and a CPR(+FHB) of 11.0%(919/8322). IUI-MFSS(n = 855) resulted in a higher +bHCG of 16.1%(149/922,P&lt;0.01) and a CPR of 12.5%(116/922).
Next, we divided cycles into NC or CLO cohorts. In couples with NC, IUI-DG(n = 420) resulted in a +bHCG of 9.3%(132/1416) and a CPR of 8.8%(124/1416). IUI-MFSS(n = 107) resulted in a +bHCG of 11.4%(15/131) and a CPR of 11.4%(15/131). In CLO cycles, IUI-DG(n = 1990) resulted in a +bHCG of 13.0%(788/6048) and CPR of 10.9% (659/6048), while IUI-MFSS(n = 496) resulted in a significantly higher +bHCG at 17.4%(122/698) and CPR at 14.3%(100/698,P&lt;0.01).
In the paired sub-analysis, NC couples (n = 30) underwent IUI-DG and subsequently IUI-MFSS. IUI-DG resulted in a 9.4% +bHCG(7/74) and 8.1% CPR(6/74). IUI-MFSS yielded a 10.2% +bHCG(4/39) and 10.2% CPR(4/39). CLO couples (n = 132) underwent IUI-DG and resulted in a 13.6% +bHCG(85/623) and 11.2% CPR(70/623), followed by IUI-MFSS yielding a 15.2% +bHCG(27/178) and 12.4% CPR(22/178).

Limitations, reasons for caution
IUI-MFSS cycles resulted in an increased proportion of progressively motile spermatozoa, with a superior genomic integrity and higher clinical outcome. The benefit of MFSS may be somewhat limited because of the low SCF of this particular cohort and only a larger case series would be able to confirm this finding.

Wider implications of the findings
DG is labor intensive, technician-dependent, and unable to meaningfully ameliorate SCF. MFSS, while reducing exposure to reactive oxygen species, grants the highest sperm progressive motility with superior genomic integrity that may be responsible for an improved pregnancy outcome.

Trial registration number
not applicable