Is genetic amniocentesis warranted when isolated choroid plexus cysts are found?

Our aim was to evaluate the prevalence of trisomy 18 in the setting of isolated fetal choroid plexus cysts and then to consider the risk of trisomy 18 versus the risks of genetic amniocentesis. Fetuses with choroid plexus cysts were prospectively obtained from a total mid-trimester population of 18861 fetuses with known outcomes. If the fetuses had trisomy 18, they were part of the study group and part of the control group if they had normal karyotypes. Scans were retrospectively reviewed for the characterization of cysts according to size, laterality, and appearance (simple or complex echo patterns). Chi-square analysis of contingency tables of results was performed. 208/18861 (1.1 per cent) fetuses had choroid plexus cysts. 201/208 (96.6 per cent) were normal fetuses or newborns, while 7/208 (3.4 per cent) of the fetuses with choroid plexus cysts had trisomy 18. Overall, 16 fetuses had trisomy 18 and seven (44 per cent) of these had choroid plexus cysts. 0/16 fetuses had choroid plexus cysts as the only sonographic finding. Although laterality or complexity of the cysts did not correlate with the presence or absence of a cytogenetic abnormality, cysts > or = 10 mm were more often associated with trisomy 18 than with a normal karyotype (P < 0.01). We conclude that the discovery of choroid plexus cysts in otherwise normal fetuses in the late second trimester does not by itself justify the risks of genetic amniocentesis.

A randomized trial of prenatal ultrasonographic screening: impact on the detection, management, and outcome of anomalous fetuses. The RADIUS Study Group.

OBJECTIVE: The objective of this randomized clinical trial was to test the hypothesis that ultrasonographic screening would significantly alter perinatal outcome as a result of the antenatal detection of fetal congenital malformations. STUDY DESIGN: Pregnant women without a specific indication for ultrasonography were randomly assigned to have either two screening sonograms (15 to 22 weeks and 31 to 35 weeks) or conventional obstetric care with ultrasonography used only as determined by the clinical judgment of the patient's physician. The frequency of birth defect detection in the screened and control populations was compared, as was the impact of discovery on pregnancy outcome. RESULTS: Major congenital malformations occurred in 2.3% of the 15,281 fetuses and infants in this study. Antenatal ultrasonography detected 35% of the anomalous fetuses in the screened group versus only 11% in the control population (relative detection rate 3.1; 95% confidence interval 2.0 to 5.1). Ultrasonography screening did not, however, significantly influence the management or outcome of pregnancies complicated by congenital malformations. Specifically, only 9 abortions were performed for anomalies among 7685 fetuses in the screened group whereas 4 pregnancies were terminated for fetal anomalies detected among 7596 control subjects. Ultrasonography screening also had no significant impact on survival rates among infants with potentially treatable, life-threatening anomalies despite the opportunity to take precautionary measures such as delivery in a tertiary center. CONCLUSIONS: Ultrasonography screening in a low-risk pregnant population had no significant impact on the frequency of abortion for fetal anomalies. Survival rates for anomalous fetuses were also unaffected by screening.