The effect of severe oligozoospermia on embryo dynamics and morphological quality

Severe oligozoospermia was associated with impaired fertilization outcomes and reduced day-3 embryo quality. A modest but statistically significant prolongation of ECC2 was observed; however, when sperm concentration was evaluated in isolation under ICSI conditions, later cleavage-stage morphokinetics and blastocyst development appeared largely preserved at the laboratory level. These findings are limited to sperm concentration alone and may be influenced by unmeasured sperm functional defects.