Advantages and limitations of chorionic villous sampling

Chorionic villous sampling (C VS) has been available for more than twenty years. Together with amniocentesis, it helps the cytogenetician to determine the fetal karyotype for prenatal diagnosis. The choice between these two methods depends on the team and the indication. CVS can now provide sufficient material for both histopathologic and cytogenetic analyses. We evaluated the accuracy of microscopic examination of CVS for detecting primary ovular, uteroplacental vascular (preeclampsia) and inflammatory disorders. Four hundred CVS were examined in the pathology laboratory of Pellegrin Hospital, Bordeaux, France, from January 1995 to February 2008. The results were analyzed according to the indication, the karyotype, the results of placental examination, pregnancy outcome and, when available (following spontaneous or medical termination), fetoplacental findings. The sample was representative of patients requiring CVS for prenatal diagnosis, with respect to maternal age, the stage of pregnancy, and the indications. When used to screen for preeclamsia (prevalence 29.6% in the sample), the sensitivity and specificity of placental biopsy were respectively 56.8% and 87.2% (76.9% in case of intra-uterine growth retardation). When used to screen for chromosomal aberrations (prevalence 7.4%), the specificity was 14.3% and the sensitivity 93.2%. The prevalence of other disorders, and particularly chronic intervillitis, was too low for meaningful analysis. This study shows that histopathologic analysis of chorionic villous samples is useful for detecting the utero placental vascular origin of intrauterine growth retardation in the absence of other clinical, biological or ultrasound signs, and that it is complementary to cytogenetic analysis. Being a simple and inexpensive examination, histopathologic analysis of C VS could be performed systematically in this indication. Its value and diagnostic signs in other settings need to be determined in larger series.