Recent insights into the in vitro culture systems for mammalian embryos.

Mammalian early embryonic development is the cornerstone for a healthy life. Any aberrations during early embryonic development may lead to adverse pregnancy outcomes. Therefore, the comprehensive study of embryonic developmental events is essential for understanding biological and pathological pregnancy. However, due to mammalian embryo development taking place in the uterus, it is hard to directly observe the developing embryos that are undergoing dramatic and complex morphologies, proliferation, and differentiation. The in vitro culture (IVC) of mammalian embryos is a pivotal model for studying developmental events. Recent advancements in establishing long-term culture systems for early mammalian embryos have allowed researchers to culture human embryos up to the embryonic day (E) 14 ethical limitations and extend mouse and macaque embryos to early organogenesis. Here, we review the development of IVC systems for mammalian embryos, emphasize the important improvements in culture elements, and offer our perspectives on potential future optimizations of IVC systems.