IMPACT OF MONOPRONUCLEAR AND TRIPRONUCLEAR PATTERNS ON ICSI OUTCOMES: ANALYZING CONTRIBUTING FACTORS AND CLINICAL IMPLICATIONS

Abstract

Objective

This study aims to elucidate the etiological factors and clinical outcomes associated with mono-pronuclear (1PN) and tripronuclear (3PN) fertilization, in comparison to the bi-pronuclear(2PN) fertilization, within the framework of ICSI cycles. We seek to examine the association between abnormal fertilization patterns and various factors, including patient demographics, cycle characteristics, semen parameters, and oocyte quality. The goal is to clarify the impact of abnormal pronuclear patterns on embryo development and clinical outcomes.

Materials and Methods

This retrospective study was conducted at the Bursa Uludağ University ART Center from 2011 to 2024. The study included a total of 2,319 ICSI cycles, categorized into four groups based on fertilization outcomes: Group 1 (n=348) comprised cycles with at least one 1PN zygote; Group 2 (n=581) comprised cycles with at least one 3PN zygote; Group 3 (n=135) included cycles with both 1PN and 3PN zygotes; and Group 4 (n=1,255) served as the control group, characterized by normal fertilization with a rate exceeding 80%. ICSI was uniformly applied to all oocytes. Fertilization status was assessed 16-18 hours after insemination to categorize cycles into the respective groups. We analyzed patients’ baseline characteristics, hormonal parameters, cycle attributes, oocyte quality, and semen parameters across the four groups to identify factors affecting fertilization outcomes. Additionally clinical outcomes, including clinical pregnancy rates and embryo development, were analyzed.

Results

A comparative analysis was conducted to evaluate baseline characteristics and ovarian stimulation profiles across study groups. The analysis revealed significant statistical differences in both female (p<0.001) and male ages (p<0.001) among the groups. No significant differences were observed in BMI (p=0.327) or infertility duration (p=0.541); however, infertility etiology (p<0.001) varied significantly between groups. Sperm concentration (p=0.552) and motility (p=0.511) values were similar across the groups. Although Group 4 exhibited a statistically significantly higher fertilization rate (p<0.001) compared to other groups, there were no notable differences in cleavage rate (p=0.413), blastulation rate (p=0.653), or implantation rate (p=0.148) among the groups.

Discussion

This study elucidates the potential impact of 1PN and 3PN fertilization on ART outcomes. Female age and infertility etiology significantly influenced abnormal fertilization rates. Similar semen parameters across groups indicate that the oocytes, rather than sperm, may be the primary source of abnormal fertilization.

Conclusion

Although abnormal pronuclear patterns negatively affect fertilization rates in ICSI cycles, they do not impact embryonic development or clinical outcomes. Further research is essential to elucidate the mechanisms behind abnormal fertilization and to develop strategies for improving clinical success rates in affected cycles.