Controversies in ART: considerations and risks for uninterrupted embryo culture.

With new time-lapse incubators, IVF laboratories have increased use of single step media, often used in an uninterrupted approach. This simplifies the culture process for embryologists, may help reduce costs, offers the potential to reduce cell handling and associated harmful environmental stressors, and improves embryo quality and outcomes. One could argue, however, that optimized quality control and culture conditions are required to implement uninterrupted culture successfully. Without impeccable laboratory conditions and oversight, while trying to reduce harmful environmental stress, the laboratory could be imparting stress. Factors such as medium evaporation and associated osmolality and pH increases, as well as volatile organic compound accumulation, could offset any advantage of reduced dish or embryo handling. When implementing uninterrupted embryo culture, attention must be paid to incubator humidity, amount, quality and type of oil used, medium formulation and protein quality, as well as laboratory air and gas supply quality, and volatile organic compound content.