Mild idiopathic lateral cerebral ventricular dilatation in utero: sonographic evaluation.

The authors prospectively studied 20 fetuses with mild dilatation of the lateral cerebral ventricles but no other detectable central nervous system abnormality. One case (5%) occurred in a diabetic pregnancy, and three (15%) involved twin pregnancies. Fifteen (75%) fetuses were male, and one (5%) had trisomy 21. Postnatal follow-up at 15-31 months showed a normal outcome in eight cases (40%), an uncertain prognosis in four cases (20%), and death in eight cases (40%). Serial antenatal sonograms were obtained in 17 cases. Among the eight cases with a normal outcome, seven demonstrated no additional sonographic abnormalities and six showed resolution of the ventricular dilatation antenatally. Conversely, all 12 fetuses with demise or an uncertain prognosis demonstrated additional sonographic abnormalities, and six showed stable or progressive ventricular dilatation on follow-up sonograms. Since mild idiopathic lateral ventricular dilatation has a widely variable prognosis, antenatal detection of this finding warrants search for additional findings and follow-up sonography.