Oocyte ability to repair sperm DNA fragmentation: the impact of maternal age on intracytoplasmic sperm injection outcomes

Abstract

To study the impact of sperm DNA fragmentation (SDF) on clinical outcomes of assisted reproductive technology in women with different age ranges. Historical cohort study. Private university-affiliated invitro fertilization center. Five hundred forty couples undergoing intracytoplasmic sperm injection cycles. Cycles were split into three groups according to maternal age: ≤36 years old (n = 285), 37-40 years old (n = 147), and >40 years old (n = 108). Semen samples were evaluated for SDF using the Sperm Chromatin Dispersion test and, for each age group, the cycles were subdivided according to SDF index: low fragmentation index (<30% SDF) and high fragmentation index (≥30% SDF). Implantation, pregnancy, and miscarriage rates. For younger patients (≤36 years old) and those between 37 and 40 years of age, no significant differences were noted in laboratory and clinical outcomes for cycles with <30% SDF or ≥30% SDF. When maternal age was >40 years of age, significantly lower high-quality day-3 embryos (54.4% vs. 33.1% and blastocyst development rates (49.6% vs. 30.2%), lower pregnancy (20.0% vs. 7.7%) and implantation rates (19.7% vs. 11.9%), and increased miscarriage rate (12.5% vs. 100.0%) were observed for cycles with ≥30% SDF compared with <30% SDF, respectively. Older oocytes, when injected with sperm derived from samples with high SDF index, develop into embryos of poor quality that lead consequently to lower implantation and pregnancy rates and higher miscarriage rates, in intracytoplasmic sperm injection cycles from women with advanced maternal age.