Objective assessments of temperature maintenance using in vitro culture techniques

To assess the ability of various facets of embryo culture (microscope stage warmers, volumes of culture media, culture vessel lids, and type of culture incubator) to maintain a constant temperature in vitro. Ability to maintain 37.0 degrees C in the microenvironment of gametes was recorded by digital thermocouple in the chosen facets of in vitro culture. Stage warmers are highly variable in their ability to maintain the set temperature (range 33.8 degrees C-37.0 degrees C after 60 s). Temperature loss in culture media is both volume and vessel dependent, and the direct heat transfer culture incubator (MINC) has superior temperature maintenance compared with a large volume air convection incubator (FORMA), where temperature regain from 35.0 degrees C to 37.0 degrees C took 5.5 min compared to >20 min. There are large measurable differences in the ability to maintain set temperature that depend on the stage warmer used, volume of media, use of vessel lids, and the type of incubator chosen for IVF culture.