Malak T M, Bell S C
Department of Obstetrics and Gynaecology, Medical School, University of Leicester, UK.
Br J Obstet Gynaecol. 1994 May;101(5):375-86. doi: 10.1111/j.1471-0528.1994.tb11908.x.
To determine the structural characteristics of the rupture site of term fetal membranes (amniochorion and decidua) that rupture spontaneously after the onset of labour.
Fourteen term fetal membranes were examined immediately after delivery at the light microscope level. Multiple samples were taken along the whole rupture site and long an axis between this site and placental edge. Morphometric analysis of the thickness of the constituent layers of the fetal membranes was performed.
Leicester Royal Infirmary Maternity Hospital.
A restricted zone of extreme altered morphology, characterised by marked swelling and disruption of the connective tissue, thinning of the trophoblast layer and thinning or absence of decidua, was identified in the rupture site of all patients. Morphometric analysis of the thickness of membrane layers showed that these changes and the ratio between the thickness of the connective tissue layers and that of the trophoblast and decidua (termed fetal membrane morphometric index) were significant between the zone of extreme altered morphology and the rest of the membranes.
The morphological features of the zone of extreme altered morphology suggests that it represents an area of structural weakness of the membranes. Since this zone did not include the whole length of the rupture site, it is likely that it was present before membrane rupture and was generated during pregnancy. We hypothesise that the zone of extreme altered morphology represents the site of initial rupture after which the tear is transmitted through the membranes to produce the rupture site. It is possible that if these changes become more extreme, then prelabour membrane rupture may occur. Further characterisation of this zone may help to understand the mechanism of its genesis and its role in predisposing the fetal membranes to rupture.
确定足月胎膜（羊膜绒毛膜和蜕膜）在分娩发动后自然破裂部位的结构特征。
在分娩后立即对14例足月胎膜进行光学显微镜检查。沿着整个破裂部位以及该部位与胎盘边缘之间的长轴采集多个样本。对胎膜各组成层的厚度进行形态计量分析。
莱斯特皇家医院妇产医院。
在所有患者的破裂部位均发现一个形态极度改变的受限区域，其特征为结缔组织明显肿胀和破坏、滋养层变薄以及蜕膜变薄或缺失。对膜层厚度的形态计量分析表明，在形态极度改变的区域与胎膜其余部分之间，这些变化以及结缔组织层厚度与滋养层和蜕膜厚度之比（称为胎膜形态计量指数）具有显著差异。
形态极度改变区域的形态学特征表明它代表了胎膜的一个结构薄弱区域。由于该区域并不包括破裂部位的全长，因此很可能在胎膜破裂之前就已存在，并且是在孕期形成的。我们推测形态极度改变的区域代表初始破裂部位，此后撕裂通过胎膜传播从而形成破裂部位。如果这些变化变得更加极端，那么可能会发生临产前胎膜破裂。对该区域的进一步特征描述可能有助于理解其形成机制及其在使胎膜易于破裂方面的作用。
