In-vitro culture of individual mouse preimplantation embryos: the role of embryo density, microwells, oxygen, timing and conditioned media

Highlights • Individual culture of preimplantation mouse embryos is detrimental during both the precompaction and postcompaction stages, demonstrated by reduced hatching rate and blastocyst cell numbers. • The effect of embryo density on singly cultured embryos is dependent on the incubator oxygen concentration. • Culture in microwell dishes increased the percentage of inner cell mass per blastocyst, and altered timing of developmental events. • Addition of embryo-conditioned media to single embryos improves hatching rates and cell numbers.