Objective: To determine the incidence of DNA fragmentation in human sperm used for intracytoplasmic sperm injection (ICSI) and to correlate any detected DNA damage with semen analysis parameters and fertilization rates in ICSI.
Design: Descriptive and correlational clinical study.
Setting: Tertiary care fertility clinic.
Patient(s): A total of 150 semen samples was collected from men in the ICSI program.
Intervention(s): For each sample, sperm wash and swim-up were performed, and the percentage of recovered sperm with DNA fragmentation was determined with the use of terminal transferase-mediated deoxyuridine triphosphate-biotin end labeling.
Main outcome measure(s): The percentage of sperm with DNA fragmentation was correlated with semen analysis parameters and ICSI fertilization rates.
Results(s): The mean (+/- SD) percentage of sperm with fragmented DNA was 14.5% +/- 1.5% and ranged from 0.5% to 75%. A significant negative association was found between the percentage of sperm with DNA fragmentation and the ICSI fertilization rate. We also observed that the motility and morphology of the ejaculated sperm were correlated negatively with the percentage of DNA fragmentation in the washed sperm recovered by the swim-up technique.
Conclusion(s): Our results suggest that when poor-quality semen samples are used for ICSI, there is a greater likelihood that some sperm selected for injection, despite appearing normal, contain fragmented DNA. Whether sperm DNA damage may contribute to failure of pronuclear formation and embryo development in some apparently unfertilized ICSI oocytes is unclear.