OP01.17: Cerebral ventriculomegaly: is the prevalence increased for fetuses with trisomy 21?

Abstract

Objective: To evaluate the correlation of trisomy 21 with ventriculomegaly diagnosed between 15 and 25 weeks. Methods: This study included 140 fetuses with cytogenetic diagnosis of trisomy 21 and detailed mid-trimester ultrasound examination in our prenatal center. This was a retrospective review of cases diagnosed between 1999 and 2006. Prenatal or postnatal karyotyping, ultrasound video and DVD recordings, still frames and ultrasound reports were analyzed in all included cases. Results: Six cases (4.3%) of mild ventriculomegaly (10–12 mm) were detected among 140 fetuses with Down’s syndrome. Five of these fetuses had additional soft marker: mild nuchal edema (3 cases), short nasal bone (4 cases), short femur and humerus (2 cases), echogenic intracardiac focus (2 cases). In three fetuses additional major anomalies were diagnosed: one case with VSD, one case with AVSD, one case with nonimmune hydrops. Only one fetus had isolated ventriculomegaly and no other signs of trisomy 21. No case of severe degree of ventriculomegaly (> 12 mm ventricular atrial diameter) was found in our collective of trisomy 21 fetuses. Conclusions: Since 4.3% of the fetuses with trisomy 21 were affected by mild ventriculomegaly the risk for trisomy 21 is increased above average when sonographic examination reveals this marker. We diagnosed 151 cases of mild ventriculomegaly in 43.490 US examinations in our center, the prevalence for all fetuses was 0.35%. However ventriculomegaly as isolated observation is rarely found. Associated anomalies involving other organs are common in cases with trisomy 21. Nevertheless we conclude that karyotyping is recommended in all cases with ventriculomegaly.