Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention


Fetal ventriculomegaly is the enlargement of the fluid-filled spaces of the brain called the ventricles. This type of ventriculomegaly occurs in babies before they are born.


Fetal ventriculomegaly may be caused by problems with brain development or the flow of cerebrospinal fluid (CSF). CSF is a fluid that surrounds and cushions the brain and spinal cord. Normally the fluid can move smoothly around the brain and spine. If CSF flow is slowed or stopped it can put pressure on the ventricles and make them expand.

Risk Factors

Conditions in the baby that may increase the risk of ventriculomegaly include:

  • Intracranial cysts
  • Spinal bifida
  • Agenesis of the corpus callosum
  • Intracerebral hemorrhage

Certain infections of the mother during pregnancy can increase the risk of fetal ventriculomegaly. Infections associated with ventriculomegaly include:

  • Cytomegalovirus—an infection caused by a type of herpes virus
  • Toxoplasmosis—an infection associated with cat feces or infected food
  • Syphilis—a sexually transmitted disease
  • Chickenpox
  • Lymphocytic choriomeningitis—a virus spread by mice (rare)


Symptoms after birth may include:

  • Rapid head growth
  • Bulging soft spot
  • Protruding scalp veins
  • Difficulty with eye movement, including inability to look up and staring downward
  • Developmental delays
  • Difficulty feeding
  • Vomiting
  • Irritability or unusual sleepiness


Fetal ventriculomegaly is often found during a routine prenatal ultrasound. Further testing may be done by specialists and after birth.

During pregnancy, the fetus’ condition may be assessed with:

Abdominal Ultrasound

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Talk with your doctor about the best treatment plan for you.


Additional ultrasounds may be done to monitor the fetus’ condition. Sometimes fetal ventriculomegaly resolves on its own.

Draining the CSF

If the condition is severe or worsens, alternative pathways will be needed to drain the CSF. This can be done by inserting a ventriculoperitoneal shunt after your child is born.


There is no known way to prevent fetal ventriculomegaly.