by EBSCO Medical Review Board


Fetal ventriculomegaly is the widening of the fluid-filled spaces of the brain. These are called the ventricles. It happens in babies before they are born.


It 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 this problem in a child are:

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

Certain infections of the pregnant 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


This health problem 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:

Abdominal Ultrasound
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Sometimes this problem 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 this health problem.


American College of Obstetrics and Gynecology 

Women’s Health—US Department of Health and Human Services 


Health Canada 

The Society of Obstetricians and Gynaecologists of Canada 


Craig A, Lober R, et al. Complex fetal care: Implications of fetal ventriculomegaly: a neurosurgical perspective. NeoReviews. 2015;16;e254. Available at: Accessed November 4, 2020.

Hydrocephalus in children. EBSCO DynaMed website. Available at: Accessed November 4, 2020.

Pediatric ventriculomegaly. Children’s National Health System website. Available at: Accessed November 4, 2020.

Ventriculomegaly and hydrocephaly. Children’s Memorial Hermann Hospital website. Available at: Accessed November 4, 2020.

Ventriculomegaly in children. Boston Children’s Hospital website. Available at: Accessed November 4, 2020.

Wright Z, Larrew TW, et al. Pediatric Hydrocephalus: Current State of Diagnosis and Treatment. Pediatr Rev. 2016 Nov;37(11):478-490.

Revision Information

  • Reviewer: EBSCO Medical Review Board Kari Kassir, MD
  • Review Date: 09/2020
  • Update Date: 05/11/2021