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Fact Sheet

What is Microcephaly?

Microcephaly is a medical condition in which the circumference of the head is smaller than expected because the brain has not developed properly, or has stopped growing. Microcephaly can be present at birth, or it may develop in the first few years of life. It is most often caused by genetic abnormalities that interfere with the growth of the cerebral cortex during the early months of fetal development. It is associated with Down Syndrome, chromosomal syndromes, and neurometabolic syndromes. The cause of Microcephaly in most babies is unknown. Some are affected because of changes in their genes. Microcephaly can also be caused by exposures during pregnancy which include: infections such as rubella (German measles), toxoplasmosis, cytomegalovirus, varicella (Chicken pox), herpes, syphilis, HIV; severe malnutrition; harmful substances such as alcohol, drugs, toxic chemicals; untreated phenylketonuria (PKU); and interruption of the blood supply to the baby’s brain during development. It has also been identified that the Zika virus infection is a cause of Microcephaly and other severe fetal brain defects. Babies born with Microcephaly will have a smaller than normal head that will fail to grow as they progress through infancy.

How is it manifested?

  • head is very small
  • high-pitched cry
  • poor feeding
  • seizures
  • increased movement of the arms and legs (spasticity)
  • developmental delays

Who is affected?

In the general population, Microcephaly due to genetic factors occurs in 1 in 30,000 – 50,000 live births, and in 1 per 10,000 births due to other causes. In some populations, frequency may be as high as 1 in 2,000 births.

How is it diagnosed or detected?

Microcephaly may be diagnosed before birth by prenatal ultrasound (a diagnostic imaging technique which uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs). Ultrasounds are used to view internal organs as they function and to assess blood flow through various vessels.

Diagnostic tests that may be performed to confirm the diagnosis of Microcephaly and identify abnormalities in the brain include:

  • Head circumference – this measurement is compared with a scale for normal growth and size.
  • X-ray – a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
  • Computed Tomography Scan (CT or a CAT scan) – a diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called “slices”), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.
  • Magnetic Resonance Imaging (MRI) – a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
  • Blood tests
  • Urine tests

Microcephaly is a lifelong condition with no known cure or standard treatment. Microcephaly can range from mild to severe, therefore the treatment options range as well. Infants diagnosed with mild Microcephaly do not experience any problems other than a small head size which requires routine check-ups to monitor growth and development.

Those with severe Microcephaly will need to monitor health problems. Developmental services and early intervention is suggested which can include speech, occupational, and physical therapies. Some medications may need to be used to treat seizures or other symptoms.

Additional Resources:

The Arc of the United
The Arc is the national organization for people with developmental disabilities and their families. It is devoted to promoting and improving supports and services, and fosters research and education.

National Institute of Neurological Disorders and
It contains information about what Microcephaly is, if and how it can be treated, the prognosis, and the research. The National Institute of Neurological Disorders and Stroke (NINDS) conducts and supports research on brain and nervous system disorders. Created by the U.S. Congress in 1950, NINDS is one of the more than two dozen research institutes and centers that comprise the National Institutes of Health (NIH). The NIH, located in Bethesda, Maryland, is an agency of the Public Health Service within the U.S. Department of Health and Human Services. NINDS has occupied a central position in the world of neuroscience for 50 years.

Centres for Disease Control and

Boston’s Children’s Hospital

Mayo Clinic

The Institutes for the Achievement of Human Potential

Books and Literature:

In a Page Pediatrics Signs & Symptoms
By Kathleen O. (EDT) Deantonis, Jonathan E. Teitelbaum, and Scott Kahan

The Official Parents Sourcebook on Microcephaly: A Revised and Updates Directory for the Internet Age
by James N. Parker and Philip M. Parker

The content contained in this document is for general information purposes. It is not the intention to diagnose or treat a child.

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