Cordocentesis at 16-24 weeks of gestation: experience of 1,320 cases.

The objective of this study was to assess the safety and efficacy of diagnostic cordocentesis at midpregnancy. 1,320 singleton pregnancies with no obvious congenital anomalies, a gestational age of 16-24 weeks, and proper indications underwent cordocentesis using the freehand technique. The results of each procedure was prospectively collected and subsequently analysed for the results and pregnancy outcomes. The mean maternal age was 31.1 years and the mean gestational age at the time of cordocentesis was 19.8 weeks. The most common indication was the risk of severe thalassaemia syndrome (69.8%) and was followed by rapid karyotyping. Of 1,320 cordocenteses, 1,281 (97%) were done successfully at the first attempt. The mean duration of the procedure was 10.5 min and was significantly longer in the first 50 cases of practice for each operator. The maternal blood contamination rate was higher when the cord insertion was targeted. The procedure-related complications included transient bleeding at puncture site (20.2%), transient fetal bradycardia (4. 3%), chorioamnionitis (two cases), and cord haematoma (one case). Of 1,281 successful cases, 184 fetuses had severe disease. The total fetal loss rate was 3.2% and the procedure-related loss was 1%. The other obstetric complications were comparable with those in the general population. We conclude that cordocentesis at midpregnancy is a useful, relatively safe, and effective procedure for prenatal diagnosis. Copyright 2000 John Wiley & Sons, Ltd.