Cerebral Ventriculomegaly. Hydrocephalus

Fetal cerebral “ventriculomegaly” and congenital “hydrocephalus” are two terms that have been commonly used indistinctly in the literature. Nonetheless, “ventriculomegaly” usually refers to the overall enlargement of the ventricles of the brain, regardless of etiopathogenesis, natural history, or outcome; conversely, “hydrocephalus” is used to define the pathological dilation of cerebral ventricles caused by an increased cerebrospinal fluid (CSF) pressure, often related to an imbalanced CSF production and/or absorption. The main causes of ventriculomegaly are structural, genetic, or infective conditions. Ventriculomegaly is diagnosed at screening ultrasound by placing the calipers at the level of the parieto-occipital sulcus, with a ventricular dilation of more than 10 mm. Fetal MRI plays an important role in detecting additional anomalies which may be overlooked also at expert brain ultrasound (so-called neurosonography), particularly when the severity of the dilation increases. The presence of associated anomalies detected either at antenatal or postnatal imaging, the severity of the condition, and the persistence and/or progression of ventricular dilation are the main determinants of postnatal outcome in fetuses initially presenting with mild to moderate ventriculomegaly. In utero ventriculo-amniotic shunting for severe fetal ventriculomegaly did not demonstrate to yield a clear improvement in outcome over expectant management. There is no proven evidence on different timing or mode of delivery to improve perinatal and neonatal outcomes in mild or moderate ventriculomegaly, and therefore timing and type of delivery should follow standard obstetric indications. For fetuses with severe ventriculomegaly or hydrocephalus and macrocephaly, elective cesarean delivery could be a reasonable option to avoid obstructed labor due to cephalopelvic disproportion although there is no univocal cut-off for head circumference to guide the decision about mode of delivery.