Microcephaly

What is microcephaly? 

Microcephaly means that a baby’s head is smaller than expected for their stage of development. It can be a sign that the brain has not grown normally during pregnancy. 

How is microcephaly diagnosed?

It is usually diagnosed on an ultrasound scan when your baby’s head measures much smaller than normal for their age. A fetal MRI or more detailed ultrasound may be offered for further assessment. 

What causes microcephaly?

There are several possible causes of Microcephaly which include: 

  • Genetic or chromosomal differences 

  • Infections during pregnancy  

  •  Poor blood supply to the brain 

  • Brain development problems 

  • Poor growth in the womb (known as fetal growth restriction) 

  • Exposure to certain medicines, alcohol, or drugs during pregnancy 

What does it mean for my baby?

The effects can be different for each baby. Some babies grow and develop normally, while others may take longer to reach milestones like sitting, walking, or talking. 

In some cases, microcephaly can affect how a baby learns, moves, sees, or hears. Your fetal medicine specialist will talk with you about what the scans show and what this might mean for your baby’s development. Regular check-ups after birth to monitor their growth and development should also be arranged. 

What happens next?

If your baby is thought to have microcephaly, you will be referred to fetal medicine for more detailed checks. 

You may be offered: 

  • A detailed scan or MRI to look more closely at your baby’s brain. 

  • Invasive testing to look for any genetic or chromosome conditions. 

  • Regular scans to check your baby’s growth and head size. 

The fetal medicine specialists will explain what the results mean, answer your questions, and help support you in making decisions about your baby’s care. 

After your baby is born, they may have further scans and check-ups to see how their brain is developing and to arrange any extra care or support they might need. 

Will it happen again?

In most cases, microcephaly happens by chance and is unlikely to happen again in future pregnancies. However, if a genetic or chromosome condition is found to be the cause, there may be a small chance it could happen again. 

Your fetal medicine or genetics team can help you to understand the cause and discuss the chance of it happening in another pregnancy.