The generation of an appropriate environment for embryonic development requires the development of a receptive endometrium. Examination of routinely fixed sections of endometrial tissue reveals a striking feature of the endometrial vasculature, namely the presence of the so-called spiral arterioles. The presence of such vascular smooth muscles enables these vessels to regulate blood flow within the endometrium. The profound changes that occur in the endometrial thickness and structure during the menstrual cycle, one would expect that endothelial growth might show similar changes over the menstrual cycle. Endothelial cells from different tissues differ in a variety of ways and, the vasculature within the endometrium shows considerable variation at different anatomical sites and it also varies during the menstrual cycle. The vascular endothelial growth factor (VEGF) system interacts with other signalling families to cooperatively regulate vessel growth and adaptation.