There are several causes of deformational plagiocephaly, and some of them occur before the baby is even born. Restricted space inside the mother’s womb can create excessive contact in certain areas of the baby’s head. This is often the cause of deformation in babies positioned in a breech position, cramped intrauterine space due to multiple births, or babies who spend excessive time with the head confined in the birth canal. Suction or vacuum instruments can also create forces that can deform the newborn skull, which is soft and pliable. The skulls of premature babies are particularly susceptible to deformation because the bone is thinner and more fragile than that of full term babies. The skull is made up of several plates with fibrous sutures between them, and it is designed for the plates to slide over each other to ease the passage of the baby’s head through the birth canal. Usually, the baby’s head becomes more symmetrical and better proportioned within about 6 weeks after birth when the deforming forces are no longer present.

Do other factors cause Deformational Plagiocephaly?

Yes, another leading cause of deformational plagiocephaly is neck tightness caused by congenital muscular torticollis or neck/trunk muscle imbalance. Torticollis is usually caused by an imbalance in the sternocleidomastoid and other neck muscles, which prevents full range of motion in the neck. It is estimated that about 85% of the babies with deformational plagiocephaly also have some kind of neck involvement. Typically, the head of a baby with torticollis is tipped to one side and rotated to the opposite shoulder, causing the head to consistently rest in the same position. The constant positioning of the head to the same side causes it to become flat in the back. Torticollis can also pull abnormally on the base of the skull and cause the ear on the same side as the posterior flattening to be pushed more forward than the opposite ear. In severe cases, the forehead can also be pushed forward on the same side, and the facial features including the eyes, cheeks, and jaw may not be symmetrical.

Another after birth cause of deformational plagiocephaly happens when the back of the baby’s head rests for prolonged periods of time against a hard surface like an infant carrier, car seat, swing or stroller. Before 1992 babies were put to sleep on their tummies, which varied the amount of force on the back of the head. But for the past decade, since the very successful “Back to Sleep” program was initiated all over the world in an effort to end Sudden Infant Death Syndrome (SIDS), infants now spend all night on their backs until they are able to roll and reposition themselves. It is estimated that the Back to Sleep program has reduced the incidence of SIDS by 40%, and it is very important to follow the regimen of putting your baby to sleep on the back. Unfortunately, the combination of the carriers we use to hold and position our babies during the day, and placing them to sleep on their backs all night has led to “a perfect storm” for the development of head shape deformities.