Leeds Fetal Medicine Unit Website

Ventriculomegaly

Definition	Posterior lateral ventricle dilatation >9mm at any gestation
Incidence	3/1000 pregnancies
Diagnosis	Ultrasound or MRI
Gestation at diagnosis	16 weeks onwards
Known cause, chromosomal or genetic association	Can be caused by infection (CMV, Toxoplasmosis), Spina bifida or intracerebral haemorrhage. Associated with chromosomal abnormalities (4%) particularly trisomy 21.
Further investigations	Karyotype and MRI
Differential Diaganosis	None
Prognosis	Dependent on karyotype and dilatation. 10-12mm (Borderline ventriculomegaly) 90% normal outcome 13-15mm (Mild ventriculomegaly) 86-33% normal outcome if isolated >15mm (Severe ventriculomegaly) or progressive poor neurodevelopmental outcome
Recurrance risk	Dependent on cause, but usually low
Research Studies	Yes. Sheffield University currently gathering cases to assess impact of MRI

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