Microcephaly (my-kroh-SEF-uh-lee) is a rare neurological condition in which an infant's head is significantly smaller than the heads of other children of the same age and sex. Sometimes detected at birth, microcephaly usually is the result of the brain developing abnormally in the womb or not growing as it should after birth.

Microcephaly can be caused by a variety of genetic and environmental factors. Children with microcephaly often have developmental issues. Generally there's no treatment for microcephaly, but early intervention may help enhance your child's development and improve quality of life.

Symptoms Causes Complications Prevention

The primary sign of microcephaly is:

  • A head size significantly smaller than that of other children of the same age and sex

Head size is measured as the distance around the top of the child's head (circumference). Using standardized growth charts, the measurement is compared with other children's measurements in percentiles. Some children just have small heads, which may measure in the third, second or even first percentiles. In children with microcephaly, head size measures significantly below average, possibly even below the first percentile for your baby's age and sex.

A child with more severe microcephaly may also have a backward sloping forehead.

When to see a doctor

Chances are your doctor will detect microcephaly at the baby's birth or at a regular well-baby checkup. However, if you think your baby's head is smaller than normal or isn't growing as it should, talk to your doctor.

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