本文应用图像分析技术对过期妊娠２０例（过期组）、延期妊娠１５例（延期组）和正常足月妊娠２９例（正常组）的胎盘绒毛和胎盘床螺旋小动脉进行形态计量学检测。结果：（１）过期组胎盘绒毛具有合体细胞结节、细胞滋养细胞增生、绒毛基底膜增厚和纤维素样坏死的绒毛数高于正常组（均Ｐ＜００５），血管合体细胞膜形成的绒毛数低于正常组（Ｐ＜００５）；延期组与对照组和过期组间均无显著区别。（２）过期组胎盘绒毛直经、周长和面积参数均小于正常组（均Ｐ＜００１）；延期组仅周长和面积参数小于正常组（Ｐ＜００５）。（３）过期、延期组胎盘床螺旋小动脉管壁增厚者高于正常组（Ｐ＜００５），而妊娠生理性改变、管壁纤维素样坏死以及急性动脉粥样化病变与对照组无明显区别。（４）过期、延期组羊水过少和羊水粪染的发生率高于正常组（均Ｐ＜００５），而新生儿低评分者发生率较高，但与正常组无明显区别。提示：过期和延期妊娠的子宫胎盘床血管和胎盘绒毛的形态学病变是导致胎盘功能逐渐低下以及胎儿预后不良的主要原因，尤其过期妊娠者更著 In this paper, placental villi and placental spiral arteries of 20 cases of overdue pregnancy (expired group), 15 cases of delayed pregnancy (deferred group) and 29 cases of normal term pregnancy (normal group) were examined by image analysis. Results: (1) The number of placental villi in the expired group was significantly higher than that in the normal group (all P <005), the number of syncytial cell membrane formation The number of villus was lower than the normal group (P <0  05); extension group and the control group and the expired group were no significant difference. (2) The placental villi straightness, perimeter and area parameters in the expired group were all less than those in the normal group (all P <001). Only the peripheral length and area parameters in the deferred group were less than those in the normal group (P <005). (3) The thickening of the wall of helical arterioles of the placenta accreta in expired and posttransplantation groups was higher than that of the normal group (P <005), while the physiological changes of pregnancy, the fibrosis of the ductal wall and the atherosclerosis lesions were compared with the control No significant difference between groups. (4) Outdated, oligohydramnios in deferred group and incidence of meconium-stained amniotic fluid were higher than those in normal group (all P <005). However, the incidence of neonates with low grade was higher but no difference with normal group. Hint: Morphological changes of uterine placental vascular and placental villi in expired and extended pregnancy are the main reasons leading to the gradual decrease of placental function and poor prognosis of fetus, especially those with late pregnancy