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Medically reviewed by Last updated on Jul 4, 2022.

What is ventriculomegaly (VM)?

VM is a buildup of cerebrospinal fluid (CSF) inside the ventricles of your baby's brain. Ventricles are spaces inside the brain where CSF is naturally produced. CSF is a clear, colorless fluid that protects and cushions your baby's brain. The extra CSF may cause the ventricles to widen and put pressure on your baby's brain. Too much pressure can cause brain swelling and lead to damage. VM can range from mild to severe. VM may go away on its own. Specialists can help you choose the best treatment for VM that is moderate or severe.


What causes VM?

The cause of VM may not be known. VM is usually a sign of an underlying medical condition. VM may be caused by a blockage that affects how your baby's brain produces or absorbs CSF.

What are the signs and symptoms of VM?

With mild VM, your baby may not have any signs or symptoms at birth. Signs and symptoms of severe VM at birth may include any of the following:

  • Wide or large head
  • Wide or full blood vessels on the scalp
  • Bulging of the soft spot on the top front of the head
  • Downward or outward position of the eyes
  • Fussiness, restlessness, or crying more than normal
  • Vomiting
  • Drowsiness
  • Poor feeding

How is VM diagnosed?

VM is usually seen during the second trimester of pregnancy. You and your baby may need any of the following:

  • A fetal ultrasound or MRI may show what is causing your baby's VM, such as a blockage. These imaging tests may also help providers measure the size of your baby's ventricles. You may be given contrast liquid to help your baby's ventricles show up better in the pictures. Tell the healthcare provider if you have ever had an allergic reaction to contrast liquid. Do not enter the MRI room with anything metal. Metal can cause serious injury. Tell the healthcare provider if you have any metal in or on your body.
    Pregnancy Ultrasound
  • Blood tests may show infection, or another cause of your baby's VM.
  • An amniocentesis test may show a genetic cause for your baby's VM. Ask your healthcare provider for more information about amniocentesis.

How is VM treated?

Treatment for VM depends on the cause. Your baby may need treatment for an underlying medical condition. Talk to your baby's healthcare provider or a specialist about treatment options. Your baby may need the following if his or her condition is severe:

  • Shunt placement helps drain extra CSF fluid through a tube from your baby's brain into his or her abdomen where it is absorbed.
  • Ventriculostomy is surgery to help drain the extra CSF fluid through a small hole in your baby's ventricle.

When should I call my baby's doctor?

  • Your baby has a fever.
  • Your baby becomes more fussy, restless, or sleepy than usual.
  • Your baby does not seem to recognize people he or she knows.
  • Your baby's symptoms return, or he or she has new symptoms.
  • You have questions or concerns about your baby's condition or care.

Care Agreement

You have the right to help plan your baby's care. Learn about your baby's health condition and how it may be treated. Discuss treatment options with your baby's healthcare providers to decide what care you want for your baby. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

Ā© Copyright IBM Corporation 2022 Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotesĀ® are the copyrighted property of A.D.A.M., Inc. or IBM Watson Health

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.