Chorionic villus sampling: a 15-year experience

The authors describe experiences gained over the period of 1984-1999 at two medical centers with chorionic villus sampling (CVS). Altogether 1,149 CVSs had been performed between the 10th and 32nd gestational weeks. Prior to 1993 the transcervical approach (TC-CVS), after 1994 the transabdominal method (TA-CVS) was used. Analysis of data collected within the framework of this study was based on the following factors: indications for sampling, complications and incidence of pregnancy loss. 91.6% of the CVSs were carried out for the purposes of cytogenetic examination of the fetus. Over the past few years an increasing number of procedures had been carried out for molecular-genetic tests (7.6% of the total number of cases). Though the primary indication for cytogenetic tests was the advanced age of the mother, a remarkable increase in the number of samplings had taken place for the purpose of examining "suspicious ultrasound findings", minor anomalies detected by ultrasound. In this group the proportion of pathological cases was significantly higher (14%) than in all the other samplings, carried out for other indications. This data in itself underlines the importance of ultrasound screening performed in the 18-20th weeks of gestation. Over the first half of the period being reviewed (1984-1993, TC-CVS), a fetal loss of 4.8% occurring within 3 weeks from the date of sampling, dropped to 1.7% in the period subsequent to year 1994 (TA-CVS). In cases of TA-CSV, both the complications and spontaneous abortions were fewer. In 74.1% of the cases studied, birth had taken place after the 37th week of gestation. Premature births (6.4%) and stillbirth rate (1.1%) did not exceed normal rates observed in the general population. On the basis of our results, it is safe to say that in prenatal diagnosis, TA-CVS is a real alternative method of mid-trimester amniocentesis and it is recommended for use at any stage of the pregnancy.