Time-Lapse Culture Improves Development and Pregnancy Outcomes of Sibling Normally Fertilized Oocytes: A Prospective...

To evaluate whether time-lapse monitoring improves embryological outcomes and clinical pregnancy rates compared to conventional culture in a sibling-oocyte study.

This multicenter-study involved 205 first-time retrieval cycles (n = 3244 mature oocytes). Sibling-oocytes from patients with ≥ 4 oocytes were randomized into conventional and time-lapse groups. The primary outcome was the good-quality blastocyst rate. Key secondary outcomes included Day-2 Good Quality Embryo (GQE) rates and clinical pregnancy rates for both fresh and frozen-thawed embryo transfers (FET).

The time-lapse group exhibited a significantly higher GQE rate on Day 2 (42.1% vs. 35.3%, p < 0.01) and a higher good-quality blastocyst rate (44.1% vs. 38.1%, p < 0.01) compared to the conventional group. While clinical pregnancy rates showed a higher trend in the time-lapse group for both fresh ET (44.4% vs. 15.8%) and FET (45.3% vs. 36.7%), these differences did not reach statistical significance. Time-lapse monitoring successfully identified embryos with early pronuclear disappearance as early as 14 h post-insemination. Morphokinetic analysis revealed that abnormal cleavage patterns were associated with significantly lower blastocyst development potential compared to normal cleavage (p < 0.01).

Time-lapse culture provides a stable environment that enhances embryo quality. While clinical pregnancy rates showed a positive trend, further large-scale studies are needed to confirm the impact on live birth rates.