a trend toward significancep = 0.057
In cycles with a lower proportion of top-quality blastocysts on day 5 (TQD5 < 50%, n = 751), the mean SDF was 16.41 ± 10.56, while in cycles with TQD5 ≥ 50% ( n = 119), it was slightly lower at 14.60 ± 9.05, showing a trend toward significance ( p = 0.057).