Endometrial remolding and angiogenesis are critical events that occur during pregnancy in order to establish uteroplacental vascular
communication. This study investigated the role of uterine telocytes (TCs) in pregnancy. We analyzed the distribution of TCs and
morphological changes in the endometrium of the gravid rabbit uterus at different stages of pregnancy: after ovulation, pre-implantation (day
7), post-implantation (days 8 and 9), and mid-pregnancy (day 14) and late (days 21–28) pregnancy. TCs gradually increased with the
progression of pregnancy. They had distinctive telopodes (TPs) and podoms, with intranucleolar chromatin. The TCs established contact with
decidual cells, growing a glandular epithelium, blood vessels, and immune cells, such as lymphocytes, neutrophils, and macrophages. The
TCs underwent morphological changes at the post-implantation phase. They acquired thick and voluminous TPs, formed an extensive threedimensional
(3D) labyrinth at mid-pregnancy, and exhibited irregular-shaped nuclei and a dilated rough endoplasmic reticulum at late
pregnancy. They also acquired a convoluted contour-formed complex network. Scanning electron microscopy (SEM) showed an extensive 3D
network in the endometrium, forming a condensed sheath at late pregnancy. Transmission electron microscopy and SEM detected
fenestrated TPs, and TCs were identified by CD34 and vascular endothelial growth factor expression. TCs also expressed matrix
metalloproteinase-9 and transforming growth factor beta-1. Results suggested that TCs might play an essential role in maternal placenta
formation, especially decidualization, regulation of uterine gland development, and neovascularization of maternal uterine blood vessels.