Undisturbed culture: a clinical examination of this culture strategy on embryo in vitro development and clinical outcomes.

ABSTRACT

OBJECTIVE: To compare the effect of a fully undisturbed culture strategy over a sequential one on embryo in vitro development and clinical outcomes in ICSI cycles. DESIGN: Retrospective cohort study. SUBJECTS: This study included 4,564 ICSI cycles performed over 5 years, including autologous and oocyte donation treatments with extended embryo culture until blastocyst in one of the two defined culture strategies. EXPOSURE Embryo cohorts were cultured in one of two culture systems a fully undisturbed culture, including an incubator with integrated time-lapse technology, one-step culture medium and embryo selection assisted by semi-automatic tools based on embryo morphokinetics, or a sequential culture, using a conventional benchtop incubator, sequential media and traditional morphological evaluation under optical microscope. The effect of the culture strategies over embryo development and clinical outcomes was quantified by generalized estimated equations, controlling for possible confounders through the inverse probability of treatment weighting method. MAIN OUTCOME MEASURES: Weighted odds ratios (OR) and 95% confidence intervals (CI) for live birth rate after fresh single embryo transfer and the cumulative live birth rate. Additionally, blastocyst development and morphology and other intermediate outcomes were also assessed. RESULTS: A significant positive association was found between the employment of undisturbed embryo culture and higher live birth rate in the first embryo transfer in both autologous (OR=1.617, 95%CI 1.074-2.435) and oocyte donation cycles (OR=1.316, 95%CI 1.036-1.672). Cumulative live birth rate after one year follow-up was also positively associated with the undisturbed culture strategy in oocyte donation cycles (OR=1.5, 95%CI 1.179-1.909), but not in autologous cycles (OR=1.051, 95%CI 0.777-1.423). Similarly, blastocyst rate, good morphology blastocyst rate and utilisation rate were positively associated with the employment of undisturbed culture in oocyte donation cycles, but not in autologous cycles. CONCLUSION: These findings imply that a culture system combining integrated time-lapse incubators with a one-step culture medium, may enhance the success rates of patients undergoing ICSI treatment by increasing the production of higher-quality blastocysts and improving embryo selection while streamlining laboratory procedures and workflow.