Abstract:
During normal human pregnancy, extravillous trophoblasts invade the maternal spiral arteries replacing the endothelial cell that normal line these vessels and degrading the musculo-elastic walls of the vessels such that they are transformed into wide-bore, low resistance conduits. This modification of the spiral arteries is essential to ensure an adequate supply of blood to the placenta during later pregnancy and two complications of pregnancy, preeclampsia and intra-uterine growth restriction, are believed to be caused by failed transformation of the spiral arteries.