CHOROID-PLEXUS CYSTS IN CHRISTCHURCH

Amongst 173 fetuses diagnosed in the second trimester as having one or more choroid plexus cysts, there was only 1 (0.58%) with a probable chromosomal anomaly. If a choroid plexus cyst was the only abnormality seen at ultrasound examination prior to 20 weeks' gestation, then there were no fetuses with either trisomy 18 or trisomy 21. If there was another abnormality seen as well as the choroid plexus cyst, then the risk of aneuploidy was 1 of 3. The association between choroid plexus cysts and aneuploidy in a community-wide study in Christchurch was significantly less than that reported in 5 recently published papers. When choroid plexus cysts are diagnosed women should be referred for high resolution ultrasound examination to look for other signs of aneuploidy. The presence of an additional abnormality, seen on ultrasound examination, is a strong indication for amniocentesis. If choroid plexus cysts are isolated we do not believe amniocentesis should be offered routinely but the management of the choroid plexus cysts by the obstetrician should be based on consultation with the patient and the knowledge of the local prevalence of the association between sonographically isolated choroid plexus cysts and aneuploidy.