Fetal Ventriculomegaly



Fetal ventriculomegaly may be caused by problems with how the brain grows. It may also be caused by the flow of cerebrospinal fluid (CSF). This fluid surrounds and cushions the brain and spinal cord. It should move smoothly. If its flow is slowed or stopped, it can put pressure on the ventricles and make them get bigger.

Risk Factors

Things that may raise the risk of fetal ventriculomegaly are:

  • Brain cysts
  • Spina bifida
  • Bleeding within the brain
  • A rare birth defect called agenesis of the corpus callosum

Certain infections in the mother can raise the risk. These are:

  • Cytomegalovirus—an infection caused by a type of herpes virus
  • Toxoplasmosis—an infection linked to cat stool or infected food
  • Syphilis—a sexually transmitted infection (STI)
  • Chickenpox
  • Lymphocytic choriomeningitis—a virus spread by mice (rare)



After birth, a child may have:

  • Rapid head growth
  • A bulging soft spot
  • Scalp veins that bulge
  • Problems with eye movement
  • Delays in development
  • Problems feeding
  • Vomiting
  • Fussiness or sleepiness


Fetal ventriculomegaly is often found during an ultrasound before the baby is born. More testing may be done by specialists and after birth.

Before birth, the baby’s health may be checked with:

  • Ultrasound
  • MRI scan
Abdominal Ultrasound
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Sometimes fetal ventriculomegaly gets better on its own. The baby's health will be monitored.

If the problem gets worse, other methods will be needed to drain the fluid. This can be done by placing a ventriculoperitoneal shunt after the child is born.


There are no known guidelines to prevent fetal ventriculomegaly.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.