Effects of Different Types of Incubators on Embryo Development and Clinical Outcomes

Abstract Background: Different types of incubators have been designed for gamete and embryo culture in the past few years. The main differences of these incubators are humidity, temperature and gas control system, which play important roles in regulating the steady state of culture media. The objective of this study was to compare the effects of different types of incubators (air jacket incubators and water jacket incubators) on embryo development and clinical outcomes in human in vitro fertilization (IVF).Methods: First, the physical performances of different incubators were tested by mimicking routine IVF procedures. After that, in a randomized controlled trial, 1013 cumulus oocyte complexes from 43 patients were equally divided into two groups, fertilized and cultured in two types of incubators to analyze the effects of different types of incubators on embryo development and clinical outcomes. Results: We found that temperature recovery time in the air jacket incubator was significantly shorter than that in water jacket incubator. Although the O2 recovering time was also significantly shorter in the air jacket incubator as compared with the water jacket incubator, no significant differences were observed in the CO2 recovering time between two groups, which was also verified by pH recovering time of culture media. Besides, the temperature of culture medium in the dish covered with oil recovered more quickly in the air jacket incubators than that in water jacket incubators. However, there were no significant differences observed in the fertilization rate, Day 3 high-quality embryo formation rate, blastocyst formation rate, good blastocyst rate and clinical outcomes between two groups.Conclusions: These results indicate that the microenvironment, especially the temperature, in air jacket incubator recover faster than that in conventional water jacket incubator, however, there were no significant differences in embryo development and clinical outcomes between two types of incubators.