胎盘床面积随着宫腔容积增减而增减，但胎盘面积并不因胎盘床面积的增减而同步增减，因此形成胎盘床与蜕膜板之间及蜕膜板与绒毛膜板之间的相对位移，并对其间的子宫螺旋动脉、绒毛组织及血管内皮细胞(VEC)造成牵拉损伤，并产生相应强度的牵拉反应，这可能是导致子痫前期-子痫(PE-E)发病的病理基础。适时终止妊娠可能为有利于保障母、胎安全的正确选择。

The placenta bed area fluctuates with the volume of the uterine. However, the placenta area is not synchronous fluctuates with the area change of placenta bed.That results in relative displacement between placenta bed and decidua basal plate and between decidua basal plate and chorionic plate.Meanwhile, the relative displacement leads to stretch injury and corresponding strength traction response on uterine spiral arteries, chorionic tissue and vascular endothelial cell(VEC). Above all are the pathological basis of the preeclampsia-eclampsia(PE-E). Terminate pregnancy at the right moment may be the right choice to keep mother and fetus being safe.