What is microcephaly?

Microcephaly is a rare condition that happens when your baby’s brain grows differently. Microcephaly can happen because your baby’s brain has not grown properly during pregnancy or stopped growing after birth.

Microcephaly is only reported in about 1 in 10,000 babies in Australia.

Your baby can be born with microcephaly, or it can happen in their first few years of life.

What are the symptoms of microcephaly?

A baby with microcephaly will have a smaller head than is expected. This is usually defined as a head circumference below the 3rd percentile.

Microcephaly is also linked to developmental delays and disability.

The severity of microcephaly can vary.

What causes microcephaly?

Microcephaly is linked to:

• Down syndrome
• other chromosomal disorders
• malnutrition during pregnancy
• malnutrition after birth
• infections during pregnancy — Zika virus, toxoplasmosis, cytomegalovirus
• problems with the blood supply to your baby's brain during pregnancy
• contact with substances that might harm your baby — such as alcohol and drugs

Microcephaly can be a sign of fetal alcohol spectrum disorder (FASD).

Often, the cause of microcephaly is unknown.

Microcephaly and Zika virus

If you get Zika virus while pregnant, it can cause birth differences for your baby, including microcephaly.

Zika virus is spread by mosquitoes and, rarely, through sexual contact. There is no risk of Zika in Australia.

Zika is found in countries in:

• Africa
• Asia
• the Western Pacific
• the Americas

If you are pregnant or planning to become pregnant, you should consider delaying your travel to Zika affected areas.

When should I see my doctor?

If you have any concerns about your child's growth or development, see your doctor or child and family health nurse.

Sometimes microcephaly can be diagnosed before your baby is born, or when your baby’s head is first measured.

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

How is microcephaly diagnosed?

Your baby can be diagnosed with microcephaly before or after birth.

Diagnosis before birth

During pregnancy, microcephaly can generally only be diagnosed by ultrasound late in your second trimester or early in your third trimester. Before this stage, a smaller than expected head may not be clear.

Diagnosis after birth

Microcephaly can be diagnosed in babies when:

• their head measurement is less than the 3rd percentile for age
• their head measurement is small compared to other growth measures
• multiple head measurements cross 2 or more lines down on their growth chart

Find out more about understanding growth charts.

Your doctor may also arrange for your baby to have an MRI scan.

How is microcephaly treated?

Microcephaly is a lifelong condition. It can’t be cured.

Your child will be looked after by a paediatrician (children’s doctor). Their treatment will depend on how severe the microcephaly is and the symptoms that they have.

Children with severe microcephaly can benefit from early intervention. These services often include therapy with:

• a speech pathologist
• an occupational therapist
• a physiotherapist

Depending on their symptoms, they may also need medicines.

Can microcephaly be prevented?

Some cases of microcephaly may be prevented. You can lower the chance of your baby having microcephaly by:

• not drinking alcohol or using drugs during pregnancy
• protecting yourself from harmful chemicals during pregnancy
• protecting yourself from infections during pregnancy (see below)

To protect yourself from infections during pregnancy, you can:

• make sure your vaccinations are up to date
• have safe sex — to protect yourself from sexually transmitted infections (STIs), including Zika
• wash your hands often
• not eat raw or under cooked food
• not change dirty cat litter — to protect yourself from toxoplasmosis
• get regular dental check-ups — to prevent gum infections

Complications of microcephaly

Children with microcephaly can have other problems. These can depend on how bad the microcephaly is. Common problems are:

• seizures
• developmental delay
• intellectual disability
• difficulty swallowing
• abnormal muscle tone — which can cause problems with movement and balance
• hearing loss
• vision problems

Some children with mild microcephaly will develop normally, with no complications.

Resources and support

You may have questions about how microcephaly will affect your child in the future. These questions can be answered by your doctor or midwife.

Rare Voices Australia provides a portal and RARE helpline offering information and resources for individuals living with a rare disease.

Read about childhood disability and parenting support.