Plagiocephaly is the medical term used to describe a misshapen, uneven or asymmetrical head shape.
There are several causes.
Caput and/or cranial moulding – after a vaginal birth, a baby’s head is usually quite pointed as the part that has come through the birth canal first may be swollen. In addition the skull may have been squashed into an unusual shape. This settles down after 24 to 48 hours.
Cephalhaematoma – this is a bruise of the skull bone that can occur after any type of birth. It is more common after a birth in which the vacuum or forceps have been required. The swelling is soft and squidgy and usually goes away after 2 to 3 weeks.
Cranial deformation sequence – in this condition, the skull shape is altered as it grows in the womb because of the position the baby has been lying in. This is more common in breech babies. The skull shape normalizes as it grows but this takes many months.
Positional plagiocephaly – because a baby’s skull bones are thin and soft, one side of the skull can get flat if the baby lies on it more than the other side. This usually develops after birth but a cranial deformation sequence (see above) can lead to positional plagiocephaly. Sometimes this happens because a baby has tight neck muscles (torticollis) which requires physiotherapy. You should try and alternate the side of the head that your baby sleeps to prevent this happening. If positional plagiocephaly does develop, it is unusual to require treatment; in particular, a helmet is very rarely required. With time, usually from the age of 6 months when babies are no longer lying on their backs 20 hours per day, the skull shape goes back to normal; this can take 6 to 12 months. It should certainly be starting to improve by 10 months and if this is not the case, you should contact your paediatrician.
Here are some techniques to help prevent your baby from developing significant plagiocephaly:
Craniosynostosis – rarely, a baby’s skull has something serious wrong with the way it is growing. Usually this is obvious because the skull does not increase in size normally, the joints in the skull bones (sutures) feel abnormal, the soft spot (fontanelle) closes early, and/or the baby’s development is delayed. This is a potentially serious condition; if there is any suggestion of craniosynostosis being the cause of a flat head, your baby should be seen by a paediatrician.