The Association Between Mature Oocyte Proportion and IVF Success: A Retrospective Analysis of 2,565 ICSI Cycles

Oya  Korkmaz; Seda  Karabulut; Elif  Yılmaz; Nuri  Delikara

doi:10.18502/jri.v26i4.21090

Oya Korkmaz Department of Histology and Embryology, Faculty of Medicine, Malatya Turgut Özal University, Malatya, Türkiye
Seda Karabulut Department of Histology and Embryology, Faculty of International Medicine, İstanbul Medipol University, İstanbul, Türkiye
Elif Yılmaz In Vitro Fertilization Center, İstanbul Medical Park Hospital, İstanbul, Türkiye
Nuri Delikara In Vitro Fertilization Center, İstanbul Kadıköy Florence Nightingale Hospital, İstanbul, Türkiye

DOI: https://doi.org/10.18502/jri.v26i4.21090

Keywords: Assisted reproductive techniques, Clinical pregnancy, Implantation rate, Live birth, Oocyte maturity.

Abstract

Background: IVF/ICSI success depends on the proportion of fertilizable metaphase II (MII) oocytes, yet direct evidence linking mature-oocyte rate to clinical outcomes remains limited. This study aimed to assess the impact of mature oocyte rate on clinical pregnancy outcomes in a large retrospective cohort of women undergoing ICSI.

Methods: A total of 2,565 women who underwent ICSI cycles at a single IVF center in Türkiye were retrospectively analyzed. Patients were stratified into three groups according to mature oocyte proportion: Group 1 (0-50%), Group 2 (51-75%), and Group 3 (76-100%). Data were analyzed per initiated ICSI cycle. Embryo transfer was performed on day 3 or day 5 post-fertilization, depending on embryo quality and patient characteristics. Logistic regression analysis was performed to assess the independent effect of mature oocyte rate on pregnancy outcomes. Statistical signi-ficance was set at p<0.05.

Results: Clinical pregnancy rates were significantly lower in Group 1 (10.23%) compared to Group 2 (28.96%) and Group 3 (29.99%) (p<0.001). Live birth and im-plantation rates increased in the higher maturity groups (7.5% vs. 21.5% vs. 22.9% and 12.1% vs. 24.3% vs. 26.0%, respectively), whereas miscarriage rates decreased (18.9% vs. 13.4% vs. 12.8%). Logistic regression analysis confirmed that a higher mature oocyte proportion was an independent predictor of clinical preg-nancy (Group 2: OR=3.4, 95%CI: 2.5-4.6; Group 3: OR=3.5, 95%CI: 2.6-4.7; p<0.001).

Conclusion: This large-scale retrospective cohort analysis demonstrates that mature oocyte proportion is an important prognostic factor of IVF success. Mature oocyte proportion should be considered an essential parameter in clinical practice and patient counseling.