Received July 19, 2022
Accepted December 02, 2022

Objective: The human embryo culture is performed in incubators with an atmosphere of ~20% oxygen, a different situation from the human tube, estimated at 5%. Currently, there are trigas incubators where the embryos can be grown in this condition.The aim of this study was to compare pregnancy and implantation rates in oocyte donation cycles, when using incubators with ~ 20% oxygen versus incubators with 5% oxygen. Methods: we designed a prospective randomized study with 50 cycles per arm. Blastulation rate, proportion of vitrified embryos and the quality of the inner cell mass of the embryo were also compared. Results: The pregnancy rate was similar in both conditions, 55.3% for 5% oxygen and 54.6% for ~ 20% oxygen. The implantation rate was 36.8% for ~ 20% and 41.8% for 5%.Patients using trigas incubators had a higher rate of embryo freezing: 30.8% versus 19.2% (p <0.0003) of patients using conventional incubators. This means that 55.4% of embryos developed in trigas was of good quality, versus only 41.8% in conventional (p<0.0002). Conclusion: we suggest that trigas incubators are more efficient and allow the development of higher quality embryos compared to conventional incubators. We expect that will be reflected in the cumulative pregnancy rate.