Appearance of head with plagiocephaly.Doctors have found that placing babies on their backs to sleep helps prevent sudden infant death syndrome (SIDS). However, babies who lie in one position too long may develop an abnormal head shape called plagiocephaly (pley-jee-uh-sef-uh-lee).

What Is Plagiocephaly?

Plagiocephaly means slanted or flattening of the head.