Microcephaly
Microcephaly
What is microcephaly?
Microcephaly is a head circumference significantly smaller than the average for the gestational age. Fetal microcephaly has been defined as head circumference smaller than 3 standard deviations below the average.
If your baby is found to have a small head circumference you will be referred to a fetal medicine specialist who will perform a detailed ultrasound scan to assess your baby’s brain and body in great detail. They will talk you through the findings and answer your questions. If microcephaly is confirmed, the fetal medicine doctor will offer you further tests (see investigations section).
What are the possible causes of microcephaly?
There are many different causes of microcephaly, some are not harmful (for example a normal variant often with strong family history of people born in a family with smaller heads), while others are more serious. More serious causes include chromosomal or genetic syndromes, fetal infections occurring in the pregnancy, toxins such as alcohol use during pregnancy, metabolic conditions, fetal growth restriction, and disorders of neuronal migration.
What is the outcome for a baby with microcephaly?
The prognosis for a fetus with microcephaly could range from normal development to a wide range of neurodisability
depending on factors such as severity of the microcephaly, and the underlying cause.
Although the outcomes for patients with non-isolated microcephaly varied widely, neurodevelopmental delay, intellectual disability, and refractory epilepsy are the most common reasons for referral to specialist paediatric services.
Studies show that the severity of microcephaly may correlate with the risk of abnormal neurological development.
Click here for The Brain Charity’s fact sheet on microcephaly.