Benirschke K
Department of Pathology, University of California, San Diego.
J Reprod Med. 1994 Apr;39(4):262-72.
Many pathologic features of the umbilical cord affect fetal well-being adversely. Excessively long or short umbilical cords may be the cause of hematomas and thrombosis of cord vessels and the placental surface, thus causing fetal death and/or thrombocytopenia. In other cases, fetal hypoxia and central nervous system damage are possible outcomes. Thrombosis is also frequently induced by velamentous insertion of the cord, as are hemorrhages when the membranous vessels rupture during parturition. Entangling and knotting of the cord, especially of excessively long cords, may lead to similar lesions and fetal death. It was recognized recently that prolonged meconium exposure to the surface of the cord can cause partial necrosis of umbilical vessels and cord ulceration. The noxious moiety of meconium also causes contraction of the umbilical vessels, leading to fetal hypoperfusion and hypoxia. A stricture at the fetal end of the cord and excessive spiralling of a very long umbilical cord are often present in cases of unexplained fetal demise, especially in early pregnancy. Less common abnormalities are obstruction of the circulation by amnionic bands and varices.
脐带的许多病理特征会对胎儿健康产生不利影响。脐带过长或过短可能是脐带血管及胎盘表面血肿和血栓形成的原因，进而导致胎儿死亡和/或血小板减少。在其他情况下，可能会导致胎儿缺氧和中枢神经系统损伤。帆状脐带插入也常引发血栓形成，分娩时膜状血管破裂则会导致出血。脐带缠绕和打结，尤其是过长的脐带，可能导致类似病变和胎儿死亡。最近发现，胎粪长时间接触脐带表面可导致脐血管部分坏死和脐带溃疡。胎粪中的有害物质还会导致脐血管收缩，导致胎儿灌注不足和缺氧。在不明原因的胎儿死亡病例中，尤其是在孕早期，常出现脐带胎儿端狭窄和很长的脐带过度螺旋。较少见的异常情况是羊膜带和静脉曲张导致的循环梗阻。
