The International Journal of Developmental Biology

Int. J. Dev. Biol. 63: 157 - 170 (2019)

Vol 63, Issue 3-4-5

Special Issue: Early mammalian development

The mammalian embryo’s first agenda: making trophectoderm

Published: 16 April 2019

Eszter Posfai*,1, Isidora Rovic and Andrea Jurisicova*,2

1The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Peter Gilgan Centre for Research and Learning and 2Lunenfeld Tanenbaum Research Institute, Sinai Health System and Departments of Obstetrics & Gynecology and Physiology, University of Toronto, Toronto, ON, Canada


One of the bottlenecks for a successful pregnancy in mammalian species is the implantation of the early embryo into the wall of the mother’s uterus. The first cell lineage the embryo sets aside following fertilization is the trophectoderm – a specialized cell type that establishes contact with the mother and mediates embryo implantation. We summarize the events that lead to the formation of the trophectoderm lineage in the preimplantation embryo and highlight key features of this cell type, which could be useful in the clinical setting for prediction of implantation outcomes.


preimplantation embryo, trophectoderm, inner cell mass, implantation

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