The uterine luminal epithelium is the first site of contact between foetal and maternal tissues during pregnancy and must undergo specialised changes for implantation to be successful. These changes, collectively termed the plasma membrane transformation (PMT), allow the blastocyst to attach to the uterus preceding the formation of a placenta. There are similarities in the morphological and molecular changes occurring in live bearing species during the PMT. Within eutherian species such as the pig, rat, and rabbit the pre-implantation period is characterised by the loss or reduction of microvilli on the surface of uterine epithelial cells leaving a smooth, flat surface for blastocyst attachment. Changes during pregnancy to the cellular cytoskeleton, adhesion molecules and junctions such as desmosomes and epithelial cadherin are similar in eutherian mammals and a marsupial, the fat-tailed dunnart, Sminthopsis crassicaudata. We characterised the uterine epithelial changes that occur during pregnancy in the fat tailed dunnart and the domestic cat (Felis catus). Immunofluorescence microscopy, transmission and scanning electron microscopy were used to compare uterine remodeling during pregnancy. The desmosomes shifted to the top third of the lateral plasma membrane of the cell and the epithelial cadherin disassociated from the lateral plasma membrane allowing for invasion by the blastocyst. We found similar changes to the cellular ultrastructure and molecular mechanisms allowing for implantation to occur in both species which have partially invasive placentation (endotheliochorial). We conclude that molecular mechanisms allowing for successful pregnancy are conserved among mammals during the early stages of pregnancy.