Vascular maladaptation prior and during implantation may lead to serious complications during pregnancy, perinatally, but also later in life (Barker hypothesis). The consequences later in life... Show moreVascular maladaptation prior and during implantation may lead to serious complications during pregnancy, perinatally, but also later in life (Barker hypothesis). The consequences later in life often appear to be related to endothelial dysfunction. Angiogenesis, the formation of new blood vessels from pre-existing ones, is an important endothelial function and plays a key role in the process of implantation and placentation. Two epidemiological studies described here, show that myocardial infarction is related to low birth weight and that assisted procreation adversely affects birth weight. An optimal intra-uterine environment forms the basis for a good perinatal outcome and is created by a receptive endometrium in which angiogenesis is crucial. To study endometrial angiogenesis, human endometrial endothelial cells were isolated. The high expression of u-PA by these cells was found to contribute to their high angiogenic properties. Furthermore, these cells depend on MT3-MMP to form tubes. The ovarian steroids overall regulate endometrial angiogenesis indirectly via the endometrial stromal cells. During implantation, the embryo takes over as the main (local) regulator by inducing angiogenesis at its implantation site through the expression of VEGF. These results provide more insight in the (patho-)physiology of endometrial angiogenesis and in the role of the embryo in this. Show less