What are the novel findings of this work?In this study of 114 cases that underwent termination of pregnancy following the detection of a major central nervous system anomaly, chromosomal microarray analysis (CMA) detected causative copy-number variants (CNVs) in 10% of fetuses. Among 86 CMA-negative cases, exome sequencing (ES) detected causative sequence variants in 44%. The ES bioinformatics pipeline also detected 13 of the causative and previously known non-causative CNVs. What are the clinical implications of this work?Our data suggest that ES could be considered as a first-tier clinical diagnostic test in the prenatal diagnosis of fetuses with major CNS anomalies, as it can detect both sequence variants and CNVs.

We have provided nomograms for assessment of the fetal brainstem. The present information supplies tools for the accurate identification of fetal mid-hindbrain anomalies providing a solid basis for a multidisciplinary approach, management and counseling of these conditions.

Fetal cerebral ventriculomegaly is a relatively common finding, observed during approximately 1% of obstetric ultrasounds. In the second and third trimester, mild (≥10 mm) and severe ventriculomegaly (≥15 mm) are defined according to the measurement of distal lateral ventricles that is included in the routine sonographic examination of central nervous system. A detailed neurosonography and anatomy ultrasound should be performed to detect other associated anomalies in the central nervous system and in other systems, respectively. Fetal MRI might be useful when neurosonography is unavailable or suboptimal. The risk of chromosomal and non‐chromosomal genetic disorders associated with ventriculomegaly is high, therefore invasive genetic testing, including microarray, is recommended. Screening for prenatal infections, in particular cytomegalovirus and toxoplasmosis, should also be carried out at diagnosis. The prognosis is determined by the severity of ventriculomegaly and/or by the presence of co‐existing abnormalities. Fetal ventriculoamniotic shunting in progressive isolated severe ventriculomegaly is an experimental procedure. After delivery, ventricular‐peritoneal shunting or ventriculostomy are the two available options to treat hydrocephalus in specific conditions with similar long‐term outcomes. A multidisciplinary fetal neurology team, including perinatologists, geneticists, pediatric neurologists, neuroradiologists and neurosurgeons, can provide parents with the most thorough prenatal counseling. This review outlines the latest evidence on diagnosis and management of pregnancies complicated by fetal cerebral ventriculomegaly.