Introduction
Time lapse imaging is rapidly adopted by IVF clinics. Besides improving embryo selection by adding evaluation criteria, it enables continuous monitoring in a highly stable and controlled environment from fertilization to transfer. Both traits have been suggested to enhance treatment success.
Aim
Differential evaluation of the effect of culture conditions and morphokinetic analysis on cycle outcome.
Methods
ICSI oocytes were cultured in a time-lapse monitoring incubator (EmbryoScope; ES) and key developmental events were annotated. A total of 239 ICSI-ET cycles of ES-incubated embryos were included. In phase-I (n=84) embryos were selected for transfer based on evaluation of static images presented on a pre-defined timeline, similar to embryos grown in conventional incubators. In phase-II (n=155) a scoring model incorporating morphokinetic criteria was implemented. Outcomes were compared to 228 cycles concurrently performed with standard incubators for patients younger/older than 35yrs with ≥5 retrieved oocytes.
Results:
Culture of embryos in the EmbryoScope or conventional incubators resulted in similar ICSI fertilization (73.6±22.1% vs. 73.2±24.0%), ET (98.1% vs. 96.2%) or pregnancy rates-PR (38.9% vs. 33.9%, for the young group & 28.4% vs. 29.1% for the older, p=NS).
The EmbryoScope scoring model significantly correlated with pregnancy rates: ET of at least one high-grade embryo resulted in PR of 40.9% compared to 25.5% (p=0.049) when only lower grade embryos were available. However, applying morphokinetic selection did not significantly increase PR as compared to conventional criteria (40.6% vs. 37.5% young patients; 33.3% vs. 20.1% older patients) in cycles performed with the ES.
Conclusion
Culture conditions appear comparable for both incubators. A more subtle ES-algorithm for embryo selection may enhance implantation rates as suggested by validation of these criteria and the trend for higher pregnancy rates.
