Biankin Sandra A, Arbuckle Susan M, Graf Nicole S
Department of Histopathology, The Children's Hospital at Westmead, Westmead, NSW, Australia.
Pathology. 2003 Aug;35(4):319-24.
Fetal blood cells enter the maternal circulation in up to 95% of pregnancies, but usually in minute volumes. Haemodynamically significant fetomaternal haemorrhage (FMH) is a much rarer event reported in approximately 1 in 2800 pregnancies. Most of the literature on this phenomenon emphasises the clinical aspects, and there is no comprehensive description of the autopsy findings. We present a series of five fatal FMH. The aim of this series is to highlight some of the autopsy findings that may prompt consideration of a diagnosis of FMH and lead to appropriate confirmatory testing and counselling of the affected couple.
The five cases were referred to the Children's Hospital at Westmead for full autopsy. A Kleihauer-Betke test was performed on the mother's blood within one week of delivery in each case.
The infants ranged in age from 27 to 40 weeks gestation (mean 36.6 weeks) with a mean birth weight of 2793 g. The estimated volumes of fetal blood lost ranged from 443 to 104 mL (mean loss 243 mL). The estimated percentage of fetal blood volume loss was an average of 107% (i.e., greater than the entire blood volume of the fetus). No other causes of hydrops were identified. Pallor was often noted, and in most cases the autopsies were markedly bloodless with large vessels collapsed. Where the brain:liver ratio could be applied, two fetuses showed a mild increase in ratio, while one infant showed moderate growth restriction with a ratio of 6.2:1 (normal ratio 2.8:1 on non-macerated fetuses over 28 weeks gestation). Placental abnormalities included thrombosis of the umbilical vein and intervillous 'haematomas' in two cases. The most striking microscopic feature was the presence of intravascular nucleated RBC within virtually all organs. Placental intervillous (i.e., within the maternal vascular compartment) nucleated red blood cells were also seen in all cases.
The autopsy findings of FMH can be subtle and easily overlooked unless a high index of suspicion is maintained. The most reliable autopsy features are pallor, subcutaneous oedema or serous effusions, and intravascular nucleated red blood cells (RBC) in organs or more specifically in the placental intervillous space. In all cases of unexplained fetal death a Kleihauer-Betke test should be performed.
在高达95%的妊娠中，胎儿血细胞会进入母体循环，但通常量极小。具有血流动力学意义的胎儿 - 母体出血（FMH）是一种罕见得多的事件，据报道约每2800例妊娠中发生1例。关于这一现象的大多数文献都强调临床方面，并且没有对尸检结果进行全面描述。我们报告一系列5例致命性FMH。本系列的目的是突出一些尸检结果，这些结果可能促使考虑FMH的诊断，并导致对受影响夫妇进行适当的确诊检测和咨询。
这5例病例被转诊至韦斯特米德儿童医院进行全面尸检。每例病例在分娩后一周内对母亲的血液进行了克莱豪尔 - 贝蒂试验。
婴儿的孕周为27至40周（平均36.6周），平均出生体重为2793克。估计胎儿失血的量为443至104毫升（平均失血量243毫升）。估计胎儿血容量丢失的百分比平均为107%（即大于胎儿的全血量）。未发现其他导致水肿的原因。常可见面色苍白，并且在大多数情况下，尸检时明显无血，大血管塌陷。在可以应用脑：肝比率的情况下，两个胎儿的比率略有增加，而一名婴儿显示中度生长受限，比率为6.2：1（妊娠28周以上非浸软胎儿的正常比率为2.8：1）。胎盘异常包括两例脐静脉血栓形成和绒毛间隙“血肿”。最显著的微观特征是几乎所有器官内都存在血管内有核红细胞。在所有病例中还可见胎盘绒毛间隙（即母体血管腔内）有核红细胞。
除非保持高度的怀疑指数，FMH的尸检结果可能很细微且容易被忽视。最可靠的尸检特征是面色苍白、皮下水肿或浆液性积液，以及器官内或更具体地说胎盘绒毛间隙内的血管内有核红细胞。在所有不明原因的胎儿死亡病例中，都应进行克莱豪尔 - 贝蒂试验。
