Understanding conceptus–maternal interactions: what tools do we need to develop?

Communication between the maternal endometrium and developing embryo/conceptus is critical to support successful pregnancy to term. Studying the peri-implantation period of pregnancy is critical as this is when most pregnancy loss occurs in cattle. Our current understanding of these interactions is limited, due to the lack of appropriate in vitro models to assess these interactions. The endometrium is a complex and heterogeneous tissue that is regulated in a transcriptional and translational manner throughout the oestrous cycle. While there are in vitro models to study endometrial function, they are static and 2D in nature or explant models and are limited in how well they recapitulate the in vivo endometrium. Recent developments in organoid systems, microfluidic approaches, extracellular matrix biology, and in silico approaches provide a new opportunity to develop in vitro systems that better model the in vivo scenario. This will allow us to investigate in a more high-throughput manner the fundamental molecular interactions that are required for successful pregnancy in cattle. The majority of pregnancy loss in cattle (and other mammals) occurs in the peri-implantation period. The contribution of endometrial dysfunction to this loss remains elusive. Furthering our understanding the function/dysfunction of the endometrium is difficult given the lack of in vitro models that appropriately recapitulate the in vivo scenario or allow high-throughput testing of conceptus–maternal interactions. Here we review the current state of the art of in vitro and in silico model development, which will allow us to test the molecular interactions required for pregnancy success in cattle and other mammalian species. Created with BioRender.com. [ABSTRACT FROM AUTHOR]