Hölzl M
Fortschr Med. 1983 Jul 28;101(27-28):1298-303.
The undisturbed circulation of amniotic fluid is the result of an intact cooperation between three compartments: maternal organism, fetus and amniotic cavity. Impairment of one of these compartments can produce a pathological increase of amniotic fluid. This is possible by animal experiment through the way of producing a hypoproteinemia in the maternal organism, comparable with the situation of maternal EPH-gestosis. By increasing the intraamnial osmotic pressure after injection of hyperosmotic solution it is also possible to produce polyhydramnios in the animal experiment. This is corresponding to the clinical situation in maternal diabetes mellitus. In studies of pregnant rabbits, the analysis of ultrastructure of the amniotic epithelium showed some alterations which are compatible with secretory activity of the yolk-sac. The epithelium of the yolk-sac is comparable with the human chorion. The amniotic epithelium has only a function as a semipermeable membrane for the diffusion of amniotic fluid. Morphological examinations of the human placenta and the amniotic sac showed an increase of placental weight in cases of polyhydramnios. There was no increase, however, of the placental surface. Disturbances of circulation in the placental villi were not seen more frequently than in a control group. In cases of polyhydramnios there were more disturbances of villous maturation. The analysis of ultrastructure of the amniotic epithelium and the surface of the umbilical cord showed some possible ways for the increase of amniotic fluid volume.
母体、胎儿和羊膜腔。其中任何一个腔室的受损都可能导致羊水病理性增多。通过在母体中制造低蛋白血症（类似于母体妊娠高血压综合征的情况），动物实验可以实现这一点。在动物实验中，通过注射高渗溶液增加羊膜腔内渗透压也有可能导致羊水过多。这与母体糖尿病的临床情况相符。在对怀孕兔子的研究中，羊膜上皮超微结构分析显示了一些与卵黄囊分泌活动相符的改变。卵黄囊上皮与人类绒毛膜相似。羊膜上皮仅作为羊水扩散的半透膜发挥作用。对人类胎盘和羊膜囊的形态学检查显示，羊水过多病例中胎盘重量增加。然而，胎盘表面积并未增加。胎盘绒毛循环障碍并不比对照组更常见。在羊水过多病例中，绒毛成熟障碍更多见。羊膜上皮和脐带表面的超微结构分析显示了羊水增多的一些可能途径。
