Prenatal diagnosis and follow‐up of 14 cases of unilateral ventriculomegaly

Objective To report prospectively the prenatal diagnosis, management and outcome of 14 cases of unilateral ventriculomegaly. Methods Fourteen fetuses were diagnosed as having one ventricle of ≥ 10 mm, as measured at the level of the atrium. Results In ten cases, the scan showed mild unilateral ventriculomegaly with an atrium width between 11 and 13 mm and this remained stable up to term. Eight of these fetuses had a magnetic resonance imaging scan in utero between 32 and 34 weeks of gestation which confirmed the diagnosis of mild ventriculomegaly without other brain abnormalities and showed a normal cortical mantle. No obvious cause was found and the outcome was normal in all cases. In four cases, the unilateral ventriculomegaly evolved rapidly with an atrium width up to 20–25 mm. Causes included atresia of the foramen of Monro, toxoplasmosis, brain atrophy and Weaver syndrome. Three underwent termination of pregnancy and the postmortem examination confirmed the diagnosis. The baby with brain atrophy and schizencephaly had a ventriculoperitoneal shunt placed at 1 month of age and has severe developmental delay at 9 months. Conclusion The prognosis of unilateral ventriculomegaly is uncertain. Examination of both ventricles during the anomaly scan should be performed, as should ultrasound follow‐up of these cases up to the end of the third trimester. Fetuses with an isolated, mild, stable unilateral ventriculomegaly seem to have a favourable neurological outcome. However, fetuses with rapidly evolving unilateral ventriculomegaly or cases associated with other brain abnormalities may have a poor neurological outcome. Copyright © 1999 International Society of Ultrasound in Obstetrics and Gynecology