Antepartum fetal blood sampling with cordocentesis. Comparison with chorionic villus sampling and amniocentesis in diagnosing karyotype anomalies.

Cordocentesis under ultrasound guidance, or percutaneous umbilical blood sampling, was first reported in 1983 by Daffos et al. Since then the method has gained importance in prenatal diagnosis. In 1,011 cases at a women's clinic in Bonn, Federal Republic of Germany, 35% of the cordocentesis cases were done for blood group incompatibilities plus intravascular transfusion in most of the cases. In the remaining 65% the indications for cordocentesis were a rapid karyotype analysis, diagnosis of fetal infections and determination of fetal acid-base status in severe intrauterine growth retardation. Chorionic villus sampling (CVS) and amniocentesis were also performed to detect karyotype anomalies. Amniocentesis constituted 78.8% of the procedures and detected 50% of the karyotype abnormalities. Cordocentesis and CVS constituted 17.3% and 3.9%, respectively, of all the procedures and diagnosed 39% and 11%, respectively, of the abnormalities. Different forms of trisomy were the most common karyotype anomaly. Translocation was noted in 22 cases. Turner's, Klinefelter and triple X syndromes and triploidy were the next major forms.