Microcephaly

Microcephaly is a condition that causes your baby’s head to be smaller than expected for their size and age. Microcephaly happens when your baby’s brain needs more time to grow or doesn’t develop completely. The size of your baby’s skull depends on the size of their brain. Brain growth happens during fetal development and infancy.

What are the types of microcephaly?

There are two types of microcephaly:

• Primary or congenital: Your baby is born with a smaller head.
• Secondary or acquired: The condition develops as your baby gets older.

How common is microcephaly?

Microcephaly is rare. Research estimates it affects about 1 in every 800 to 5,000 babies in the United States.