Deformational plagiocephaly is a condition in which a baby's head has an uneven or irregular shape.
It usually occurs prior to birth as a result of pressure inside the uterus, but it can also happen after birth. After birth, this condition is generally caused by the baby frequently lying in the same position. More than 80 percent of the brain's growth occurs during the first 13 months of life. If an infant has mild deformational plagiocephaly, it usually corrects itself. After 12 to 13 months of age, the use of an orthosis is not as effective and is less likely to change the shape of the baby's head.