Flat heads in babies is an increasingly common problem, with 46% of children having a flat spot (stat from 2013). Parents of babies with flat heads often ask why their child has a flat head to begin with.
While there are a number of reasons why your baby may have a flat head, we will be focusing on the most common cause – positional plagiocephaly. Interestingly, the prevalence of flat heads in babies has increased since the SIDS campaign teaching parents about babies sleeping on their backs. While reducing SIDS is an incredible thing (of course), the increase in plagiocephaly has been linked to sleeping on the back.
Why does a baby develop positional plagiocephaly?
A flat head, also known as positional plagiocephaly, is when part of the back of the head becomes flattened rather than its usual rounded appearance. Babies are at risk of having flat heads because their heads are soft and malleable.
When a baby is born, you may have noticed your nurse or paediatrician checking their fontanelles, or open spaces between the bones. In fact a baby’s cranial bones are separated by sutures and fontanelles, which are spaces between the bones. These spaces allow the cranial bones to overlap each other when exiting the birth canal for an easier fit. Once born, the spaces allow the brain and head to grow until it is adult size, when the fontanelle closes over and the sutures form a fused bond.
A baby’s skull bones are able to move according to the pressure placed on them. The most current theory behind positional plagiocephaly is that constant pressure on the skull causes the deformation in it’s shape. Additionally, it is more common in babies with a neck strain such as torticollis. If your baby is born with a head preference, you might notice they sleep and lay with their head turned one way. Some babies even get upset if you try and turn the head the opposite way. Prolonged pressure on one side of the head will lead to changes in head shape.
It’s also important to remember that this head moulding can begin before the birth, particularly if the baby’s womb positioning isn’t optimum and their head is pushed against the ribs or pelvis. Often babies can enter the world with heads moulded to their in-utero environment. A pre-existing flat spot can often lead to a head preference of turning one way (onto the flat spot), which may worsen the problem. Malpositioned babies may also develop haematomas (swellings on the head) from the birth process. You may notice your baby turns away from the swollen area to avoid pressure on it.