Low oxygen concentrations for embryo culture in assisted reproductive technologies.

During in vitro fertilisation (IVF) procedures, human preimplantation embryos are cultured in the laboratory. While some laboratories culture in an atmospheric oxygen concentration (˜ 20%), others use a lower concentration (˜ 5%) as this is more comparable to the oxygen concentration observed in the oviduct and the uterus. Animal studies have shown that high oxygen concentration could have a negative impact on embryo quality via reactive oxygen species causing oxidative stress. In humans, it is currently unknown which oxygen concentration provides the best success rates of IVF procedures, eventually resulting in the hightest birth rate of healthy newborns.