My baby has ventriculamegaly on ultrasound scan

Introduction

This leaflet is aimed at pregnant women with suspected finding of a ventriculomegaly on ultrasound examination. The leaflet should only be given with a consultation with a senior obstetrician or fetal medicine specialist.

What is ventriculomegaly?

The brain and spinal cord is surrounded by a clear, colourless fluid called cerebrospinal fluid (CSF). This is a clear, watery liquid that surrounds the brain and spinal cord, and also fills the cerebral ventricles. Ventricles are four naturally occurring spaces within the brain; these include two lateral ventricles, a 3^rd and a 4^th ventricle. During the routine anatomy scan at approximately 20 weeks, the width of the lateral ventricles is measured, as part of a check for normal anatomy. There can be a wide variation in this measurement that is considered normal, however when the ventricles have more than 10mm of fluid measured within them it is referred to as ventriculomegaly.

Most babies with a ventricular measurement of 10mm or more are completely normal however as the measurement is considered out with the normal range, you will be offered a referral to see a doctor in the Fetal Medicine Unit.

What causes ventriculomegaly?

In most cases the brain and ventricles are completely normal, and that the apparent increase in size is simply a reflection of normal, natural variation in the way that the brain develops and appears on scan during pregnancy.

Occasionally, ventriculomegaly can be a sign of a condition affecting brain development. For example, there might be a partial blockage to the flow of fluid out of the chambers (aqueduct stenosis), or it might be that there is a problem with the overall structure of the brain tissue.

Other possible explanations include problems that affect not only the brain, but also the rest of the baby. Examples include infection with several common viruses such as Cytomegalovirus (CMV) or Toxoplasmosis, many of which don’t cause an obvious maternal illness.

Other possibilities include either a chromosome problem such as Down’s syndrome (or Trisomy 21), or a genetic syndrome (due to a fault with a single genetic instruction).

What does it mean for my baby?

The outcome for babies with any of these conditions is highly variable, and is very dependent on the nature of the problem. In many cases, if the remainder of the scan is completely normal, the most likely explanation is that this is a variation of normal with little or no effect on the long term development of the baby. In other circumstances this finding will be more significant and have some effect on how the baby will develop throughout childhood and as an adult. Your fetal medicine doctor will discuss this with you in more detail following your specialist ultrasound scan.

What will happen now?

During your fetal medicine appointment an ultrasound scan will be performed and the consultant will discuss the findings with you. The ultrasound scan is to assess your baby’s brain in detail but also to assess the remainder of your baby’s anatomy and wellbeing to give an overall assessment.

If ventriculomegaly is confirmed, you will be offered further appointments for ultrasound scans and assessments of the baby’s wellbeing throughout the remainder of your pregnancy. You will also be offered additional tests to find the cause of the ventriculomegaly and the impact it may have on your baby in the longer term.

These tests include a blood test to check if you have recently had an infection.

You will also be offered a test called amniocentesis to rule out the possibility of a variety of different chromosomal abnormalities such as Down’s Syndrome. This test involves introducing a fine needle into the uterus and taking a sample of amniotic fluid from around the baby. This will be discussed in full with your specialist fetal medicine doctor and midwife. (See separate information leaflet).

Recent studies have shown that the use of Magnetic Resonance Imaging (MRI) to image the baby’s brain during the pregnancy can improve diagnostic accuracy and be of help ruling out additional structural problems in the brain in cases of ventriculomegaly. For this reason you will be offered a separate appointment to attend for an MRI scan at the Royal Victoria Infirmary (RVI), Newcastle upon Tyne.

It can sometimes take a few weeks to obtain the final results from all of these tests. You will be informed of the results by telephone or at your follow up appointment.

For further information

For further information please contact:

Fetal Medicine Department,
Royal Victoria Infirmary
(0191) 2825837
Monday –Friday 9-5pm

Be sure to ask questions to the doctor supplying you with this leaflet and make a note of any questions you would like to ask at your next Fetal Medicine Unit appointment.

Antenatal Results and Choices
0845 077 2290 or 0207 713 7486 via mobile

North of Tyne Patient Advice and Liaison Service (PALS)
0800 0320202
Monday to Friday 9.00-4.30pm (answer phone out of hours)
Email: [email protected]