Analysis of the key factors for the high success rate of fresh embryo transfer in vitro. Fresh embryo transfer in vitro is a modern assisted reproductive technology that can help many infertile couples realize their dreams of having children. However, the success rate of fresh embryo transfer in vitro is not 100%, and there are many influencing factors. The key factors for the high success rate of fresh embryo transfer in vitro are analyzed below from four aspects: nutrition, psychology, treatment and technology. Nutritional Factors Nutrients have a great influence on embryonic development. Proper nutritional intake can promote embryonic development