What is Microcephaly?

Microcephaly is a condition where a baby’s head is much smaller than expected. During pregnancy, a baby’s head grows because the baby’s brain grows. Microcephaly can occur because a baby’s brain has not developed properly during pregnancy or has stopped growing after birth, which results in a smaller head size. Microcephaly can be an isolated condition, meaning that it can occur with no other major birth defects, or it can occur in combination with other major birth defects.

What is severe microcephaly?

Severe microcephaly is a more serious, extreme form of this condition where a baby’s head is much smaller than expected. Severe microcephaly can result because a baby’s brain has not developed properly during pregnancy, or the brain started to develop correctly and then was damaged at some point during pregnancy.

Other problems

Babies with microcephaly can have a range of other problems, depending on how severe their microcephaly is. Microcephaly has been linked with the following problems:

• Seizures
• Developmental delay, such as problems with speech or other developmental milestones (like sitting, standing, and walking)
• Intellectual disability (decreased ability to learn and function in daily life)
• Problems with movement and balance
• Feeding problems, such as difficulty swallowing
• Hearing loss
• Vision problems

These problems can range from mild to severe and are often lifelong. Because the baby’s brain is small and underdeveloped, babies with severe microcephaly can have more of these problems, or have more difficulty with them, than babies with milder microcephaly. Severe microcephaly also can be life-threatening. Because it is difficult to predict at birth what problems a baby will have from microcephaly, babies with microcephaly often need close follow-up through regular check-ups with a healthcare provider to monitor their growth and development.

Causes and Risk Factors

The causes of microcephaly in most babies are unknown. Some babies have microcephaly because of changes in their genes. Other causes of microcephaly, including severe microcephaly, can include the following exposures during pregnancy:

• Certain infections during pregnancy, such as rubella, toxoplasmosis, or cytomegalovirus
• Severe malnutrition, meaning a lack of nutrients or not getting enough food
• Exposure to harmful substances, such as alcohol, certain drugs, or toxic chemicals
• Interruption of the blood supply to the baby’s brain during development

Some babies with microcephaly have been reported among mothers who were infected with Zika virus while pregnant. Researchers are studying the possible link between Zika virus infection and microcephaly.

CDC continues to study birth defects, such as microcephaly, and how to prevent them. If you are pregnant or thinking about becoming pregnant, talk with your doctor about ways to increase your chances of having a healthy baby.

Treatments

Microcephaly is a lifelong condition. There is no known cure or standard treatment for microcephaly. Because microcephaly can range from mild to severe, treatment options can range as well. Babies with mild microcephaly often don’t experience any other problems besides small head size. These babies will need routine check-ups to monitor their growth and development.

For more severe microcephaly, babies will need care and treatment focused on managing their other health problems (mentioned above). Developmental services early in life will often help babies with microcephaly to improve and maximize their physical and intellectual abilities. These services, known as early intervention, can include speech, occupational, and physical therapies. Sometimes medications also are needed to treat seizures or other symptoms.