Blastocyst development in assisted reproductive technologies: a narrative review evaluating its role as a surrogate marker for pregnancy outcomes and live birth success

Abstract

There is an urgent global need to improve in vitro fertilization success rates and expand access to services. Specific to the in vitro fertilization laboratory, challenges such as standardization and a shortage of trained embryologists hinder quality and limit service availability. Current standards for product approval rely on demonstrating comparable pregnancy rates, requiring extensive patient involvement and time-consuming trials, which may be further hindered by patient reluctance to participate in clinical trials. Efficient assessment of new protocols and devices for assessing human assisted reproductive technology requires considering intermediate endpoints and markers to complement conventional endpoints. This review explores blastocyst development as a potential surrogate marker for pregnancy. It examines the correlation between blastocyst development and implantation potential, evaluates how culture conditions and other factors affect outcomes, and discusses the evidence supporting an absence of adverse effects of embryo culture on perinatal and offspring health. The conclusion strongly suggests that blastocyst development could serve as a valuable surrogate for establishing equivalency of pregnancy and live births in new assisted reproductive technology protocols. This review underscores the need for a surrogate marker of quality and presents evidence supporting the utility of blastocyst use rate as a sufficient indicator.