Although it is uncommon, understanding when it can be detected, which scans are used and what happens after an abnormal finding can help parents navigate the next steps with greater clarity.
To understand Dandy-Walker malformation and how it is detected during pregnancy, we spoke with Dr Megha Mittal, Senior Consultant, Obstetrics & Gynaecology, Apollo Spectra Hospital Delhi.
What Is Dandy-Walker Malformation?
Dandy-Walker malformation is a rare congenital brain abnormality involving the development of the cerebellum and the fluid-filled spaces around it.The cerebellum is the part of the brain involved in balance, coordination and movement. In Dandy-Walker malformation, the development of the cerebellar structures and the fourth ventricle can be altered, and a fluid-filled space called a posterior fossa cyst may develop.
The condition can vary considerably from one baby to another. Some babies may have other brain or organ abnormalities along with it.
What Causes Dandy-Walker Malformation?
The exact cause is not always known. It develops while the baby's brain is forming during pregnancy.Possible associations include:
- Genetic or chromosomal conditions
- Other congenital abnormalities
- Certain developmental factors during early pregnancy
Can Dandy-Walker Malformation Be Detected During Pregnancy?
Yes. Doctors may suspect Dandy-Walker malformation during the second-trimester ultrasound, particularly during the detailed mid-pregnancy anatomy scan.Doctors examine the baby's brain structures and look at areas such as:
- Cerebellum
- Fourth ventricle
- Posterior fossa
- Cisterna magna
- Overall brain anatomy
- Dr Megha Mittal, Senior Consultant, Obstetrics & Gynaecology, Apollo Spectra Hospital Delhi
How Is Dandy-Walker Malformation Diagnosed?
Doctors may use several tests to understand the baby's brain development:- Detailed ultrasound: A targeted foetal brain scan can provide a closer look at the cerebellum and posterior fossa.
- Foetal neurosonography: A foetal medicine specialist may perform a specialised ultrasound examination when a brain abnormality is suspected.
- Foetal MRI: MRI may provide additional information about the baby's brain when ultrasound findings are unclear or more detailed assessment is needed.
- Genetic testing: Depending on the ultrasound findings, doctors may discuss genetic or chromosomal testing.
Can Dandy-Walker Malformation Affect the Baby?
The impact can vary widely.Some babies may have relatively mild problems, while others may experience developmental or neurological difficulties. The outcome often depends on whether the Dandy-Walker malformation occurs alone or alongside other brain, genetic or structural abnormalities.
Possible concerns may include:
- Problems with movement and coordination
- Developmental delay
- Increased pressure inside the brain due to excess cerebrospinal fluid
- Seizures in some children
- Other neurological or developmental concerns
Is Dandy-Walker Malformation Associated With Other Conditions?
Yes. Dandy-Walker malformation can sometimes occur along with abnormalities involving other parts of the brain or other organs.Depending on the ultrasound findings, doctors may examine:
- The heart
- Kidneys
- Limbs
- Spine
- Other brain structures
Can Dandy-Walker Malformation Be Treated During Pregnancy?
No treatment can correct the brain development abnormality before birth.Management during pregnancy generally focuses on detailed assessment, monitoring and understanding whether other abnormalities are present. The medical team may also plan appropriate care after birth based on the baby's expected needs.
If excess fluid develops in the baby's brain, the newborn may require further neurological evaluation and treatment after delivery.
What Happens After Birth?
After birth, the baby may undergo further evaluation to understand the extent of the condition.Doctors may recommend:
- Brain imaging such as ultrasound, MRI or CT when appropriate
- Neurological assessment
- Developmental monitoring
- Evaluation for hydrocephalus
- Physiotherapy or other supportive therapies if needed
When Should You See a Foetal Medicine Specialist?
A foetal medicine consultation may be recommended if:- An ultrasound shows an unusual brain finding
- The cerebellum or posterior fossa appears abnormal
- Other foetal abnormalities are detected
- A doctor recommends foetal neurosonography or MRI
- There is a previous pregnancy affected by a significant congenital abnormality
Whether you’re pregnant, a new mom, or navigating postpartum, you don’t have to do it alone. Join our support group to connect, share, and support one another.
FAQs on Abnormal Brain Development in Pregnancy: What Does It Mean?
- Does Dandy-Walker malformation mean the baby has hydrocephalus?
Not necessarily. Hydrocephalus can occur in some babies with Dandy-Walker malformation, but it is not present in every case. Doctors assess the brain and fluid spaces carefully to determine whether excess fluid has developed. - Can Dandy-Walker malformation affect delivery?
Not necessarily. The timing and mode of delivery usually depend on the overall pregnancy and the baby's condition, not the diagnosis alone. Your obstetric and foetal medicine team can recommend an appropriate delivery plan based on the complete assessment.