Accuracy and Safety of Late Chorionic Villus Sampling in High-Risk Pregnancies in 8599 Cases

To evaluate the association between late CVS (placental biopsy, later than 13 weeks of gestations) and complications between sampling and delivery in 8599 cases in the Department of Obstetrics and Gynecology of a private hospital Podobnik, Zagreb, Croatia.

Late chorionic villus sampling under ultrasound guidance was carried out in prospective monocentric cohort study of 7859 (91.4%) cases in the second trimester and 700 (8.6%) cases in the third trimester of pregnancy. Out of 8599 late CVS cases, 1476 (17.2%) were performed because of suspicious ultrasonographic findings.

In 43 patients (0.50%), complications were found between sampling and delivery. There were only 12 (0.15%) spontaneous abortions four to six weeks after late CVS (before 28 weeks). We found 190 (2.3%) chromosomal abnormalities. In the group with suspicious ultrasonographic findings, comparing 1476 cases, we found significant oligohydramnios in 375 (25.4%), significant polyhydramnios in 197 (13.3%) and chromosomal abnormalities in 125 (8.5%) cases. Among the 190 patients with chromosomal abnormalities, ultrasonographic findings were detected in 98 (49.2%) after the 22th week of pregnancy.

Late CVS is a safe method of invasive prenatal diagnosis with lower spontaneous abortions rate (0.15%). This method, applicable after 13 weeks of gestation, offers a more flexible approach to invasive prenatal diagnosis of chromosome abnormalities, in very specialized fetal-maternal centres for this method.