Microscopic investigation of villi from chorionic villous sampling

Abstract

The aim of the present study was to investigate the morphology of cytogenetically normal chorionic villi from chorionic villous sampling (CVS) specimens. This information can serve as a reference for morphological investigation of cytogenetically abnormal CVS specimens. We were also interested in any relationship between chorionic villous architecture and the outcome of pregnancy. In a reference group (n = 94, normal karyotype and ongoing pregnancies), we observed a considerable variation in villous diameter (range 116-377 μm) and vascular density (range 0.5-6.7 vessels/villus) and a high incidence of morphological criteria, classically mentioned in relation to chromosomal or other abnormalities, such as: fibrinoid deposition (74.5%), trophoblastic layer degeneration (3.2%) and abnormal proliferation (7.4%), avascular villi (54.2%), stromal oedema (55.3%), trophoblastic inclusions (23.4%) and fibrosis (23.4%). In the cytogenetic abnormal group (n = 10), neither the diameter nor the vascular density of the villi differed from the values observed in the reference group. In the reference group, we only observed a tendency for larger birthweights in relation to respectively larger and more vascularized villi. It is concluded that in CVS specimens, chorionic villous architecture and morphological criteria do not have any clinical relevance, neither do they have any important predictive value.