Interest of Morphokinetic Parameters of Early Embryonic Development in the Birth Rates in Vitro Fertilization

In France, nearly 3% of children are conceived by the technique of Assisted Reproductive Medicine, of which nearly 70% by in vitro fertilization (IVF). The rates of clinical pregnancy by oocyte retrieval or embryo transfer have not changed much. The use of mono-embryo transfer reduces the risk of multiple pregnancies and associated obstetric complications. The choice of embryo to transfer or freeze is a key element in improving the chances of success of IVF. It is usually based on conventional morphological criteria (reference method) that are punctual, qualitative and subjective. However, embryo morphology at early stages has little predictive value for obtaining a late-stage embryo and its chances of implantation. The recent use of time-lapse technology during embryonic culture makes it possible to associate morphological criteria with continuous monitoring of the kinetics of embryonic development. The choice of the embryo to be transferred is then made according to morphokinetic criteria (conventional morphological criteria to which are added the data of the kinetics of embryonic development). Two recent retrospective studies give contradictory results, the first shows higher birth rates in the group of embryos selected according to conventional morphological criteria, the second concludes that morphokinetic analysis is superior. Morphokinetic criteria would also be more objective and reproducible. However, the use of morphokinetic parameters remains controversial in the literature.