any anomaly of the physiological conversion of the uterine spiral arteries into highly dilated vessels by the action of invading trophoblast; in pregnancy, trophoblast invasion and uterine spiral artery remodeling are important for lowering maternal vascular resistance and increasing uteroplacental blood flow; this process involves loss of smooth muscle and elastic lamina from the vessel wall, and significant dilation at the mouth of the vessel; impaired spiral artery remodeling has been implicated in preeclampsia, fetal growth restriction, and preterm labor