The importance of the day of embryo transfer during in vitro fertilisation

Abstract

The timing of embryo transfer, which aligns with different stages of embryo development, is an important element of in vitro fertilisation (IVF). This article briefly describes the main phases of IVF treatment, embryo development and transfer policies, cumulative live birth rates, and the key findings of the authors’ research. In vitro fertilisation (IVF) is a well established treatment for infertility and has been responsible for the birth of more than 10 million children worldwide since 1978.1 An IVF cycle includes ovarian hyperstimulation with hormones, oocyte retrieval, and then fertilisation and embryo culture in the laboratory.23 In most laboratories worldwide, embryos are cultured in vitro for three to six days, and the embryos with the highest chance of resulting in a live birth are selected for intrauterine transfer. Surplus embryos are cryopreserved for future use if a live birth is unsuccessful after an initial transfer or more children are planned. IVF, with or without intracytoplasmic sperm injection (ICSI), involves the handling of sperm cells and oocytes (gametes) and embryos outside the human body. In IVF, thousands of sperm cells are used to inseminate oocytes in the …