Randomized controlled trial comparing embryo culture in two incubator systems: G185 K-System versus EmbryoScope.

Objective: To study whether the closed culture system, as compared with a benchtop incubator with similar culture conditions, has a positive impact on intracytoplasmic sperm injection (ICSI) outcomes.

Design: Randomized controlled trial.

Setting: University hospital.

Patient(s): A total of 386 patients undergoing ICSI cycles with at least six mature oocytes were randomized.

Intervention(s): Of these patients, 195 were assigned to the group with culture in a time-lapse imaging (TLI) system (EmbryoScope) and 191 to the group with culture in the G185 K-System (G185).

Main Outcome Measure(s): Rate of implantation (primary endpoint) and embryo morphology grade.

Result(s): No significant differences were found in the implantation rates. The proportion of high-grade embryos on day 2 was significantly higher in the TLI group compared with the G185 group (40.4% vs. 35.2%). The impact of the incubator on embryo morphology remained significant in multivariate analysis, which took into account the woman's age, the rank of attempt, and the smoking status (TLI vs. G185: odds ratio = 1.27; 95% confidence interval, [1.04-1.55]). No difference was found in the mean number of frozen embryos, even though the total proportion of frozen embryos was significantly higher in the TLI group than in the G185 group (29.5% vs. 24.8%).

Conclusion(s): No difference in implantation rate was found between the two incubators for fresh cycles. It remains to be determined whether the observed differences in embryo morphology and the total number of embryos cryopreserved would translate into higher cumulative outcomes with subsequent frozen embryo transfers.

Clinical Trial Registration No: NCT02722252.