Embryo transfer is a procedure used in assisted reproductive technology (ART) in which a fertilized egg (embryo) is transferred from a laboratory dish to the uterus of a female. The purpose of this procedure is to establish a pregnancy. Embryo transfer is typically done after in vitro fertilization (IVF), when the embryo has been created in a laboratory setting. During the embryo transfer procedure, a thin catheter is used to insert one or more embryos into the uterus. The procedure is generally done under ultrasound guidance. The success rate of embryo transfer depends on a variety of factors, including the quality of the embryo, the age of the female, and the experience of the physician performing the procedure.