Morphokinetic parameter comparison between embryos from couples with high or low sperm DNA fragmentation index.

OBJECTIVE

To study whether time-lapse imaging can identify morphokinetic events impacted by a high sperm DNA fragmentation index (DFI).

DESIGN

Historical cohort study.

SETTING

Private university-affiliated in vitro fertilization center.

PATIENT(S): A total of 978 zygotes cultured until day 5 in a time-lapse imaging incubator between March 2019 and August 2020, derived from 118 patients undergoing intracytoplasmic sperm injection as a result of idiopathic male factor infertility.

INTERVENTION(S): Kinetic markers from the point of insemination were recorded. Generalized linear mixed models adjusted for potential confounders followed by the Bonferroni post hoc test were used to compare the timing of specific events in patients with a low (<30%) or high (≥30%) sperm DFI. The recorded kinetic markers were the following: timing to pronuclei appearance and fading; timing to 2, 3, 4, 5, 6, 7, and 8 cells; and timing to start blastulation and blastulation.

MAIN OUTCOME MEASURE(S): Timing to blastulation.

RESULT(S): Embryos derived from sperm samples with ≥30% DFI showed significantly slower divisions compared with those with <30% DFI (mean differences of 0.7 hours in timing to pronuclei appearance, 1.2 hours in timing to pronuclei fading, 1.5 hours in timing to 2 cells, 2.5 hours in timing to 3 cells, 1.8 hours in timing to 4 cells, 3.3 hours in timing to 5 cells, 3.1 hours in timing to 6 cells, 3.2 hours in timing to 7 cells, 2.7 hours in timing to 8 cells, 8.4 hours in timing to start blastulation, and 3.8 hours in timing to blastulation). The incidences of reverse or direct cleavages (9.3% vs. 4.4%; odds ratio [OR], 2.24; 95% confidence interval [CI], 1.32-3.77) and multinucleation at 2-cell (18.9% vs. 12.0%; OR, 1.70; 95% CI, 1.12-2.58) and 4-cell (14.2% vs. 6.4%; OR, 2.42; 95% CI, 1.57-3.74) stages were significantly higher in embryos deriving from ≥30% DFI than from <30% DFI. The KIDScore ranked significantly different between embryos derived from samples with <30% and ≥30% DFI. Continuous DFI was positively correlated with all timings of specific events and with the incidences of abnormal cleavage patterns (OR, 1.042; 95% CI, 1.025-1.059) and multinucleation at 2-cell stage (OR, 1.053; 95% CI, 1.030-1.076) and inversely correlated with the KIDScore rank (B, -0.218; 95% CI, -0.044 to -0.007). No significant differences were observed in clinical outcomes between the groups.

CONCLUSION(S): Embryo morphokinetic parameters are negatively impacted by high sperm DFI, resulting in delayed cell cleavage and blastulation.