A Heady Topic: What Your Newborn’s Head Shape Means

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When we see a newborn baby, we all have certain expectations of what she will look like. After all, we’ve all seen pictures in books and magazines and images on television and our computer screens. So when that day comes when your own baby is born, what if she doesn’t resemble that picture on the baby food jar? Is there something wrong?

Rest assured, more likely than not the answer to this question is no. There are lots of normal variants in how new arrivals look. That closed eye will likely open. That rash will likely go away. And this blog’s concern, that “funny looking head,” is probably a benign, self-resolving thing as well.

Variants in head shape, as well as “bumps” present in the scalp area, are not uncommon. It’s helpful to know the reasons they happen as well as their usual timelines for resolution. We’ll discuss some of the most common ones. But first, a little introduction to that area.

Some Baby Skull Basics

What we commonly see with baby heads can be explained by knowing what structures lie underneath. The skull as we know it in older people is made up of relatively sturdy bones fused together. In an infant, however, the bones are fairly thin and soft, and they’re not yet fused, meaning individual bones can move upon each other and even overlap.

Since a skull, is after all, living tissue, it’s supplied and surrounded by the same liquids as the body’s other organs. Blood flows to and from the bones, and a lot of what causes baby head bumps is related to blood flowing directly over the bone, which is surrounded by a membrane called the periosteum. Also, skull tissue, like other tissues in the body, is surrounded by other fluid, known as extracellular fluid, which can build up if it has nowhere to go.

What Can Happen (and Why)

Quite literally, babies have to go through a lot in order to be born. There they are, innocently lying in the uterus. Then, suddenly, it’s birthing time, and the labor process begins. During this process, pressure from the uterus begins to squeeze out the baby. The cervix, vagina and pelvis do their best to widen to accommodate the newborn-to-be, but it’s still a very tight fit. Thus, during even a very normal birth, there’s quite a bit of pressure, and this sometimes affects the baby’s head in a way that, while usually harmless, is very noticeable during those first few days of life.

We’ve talked a little bit about the “why”; now onto the “what.”

Molding is a process whereby the unfused skull bones are pushed against each other in an overlapping manner. This produces a characteristic “cone-shaped head” as well as a tempoaray loss of the baby’s normal “soft spots,” or fontanelles. This generally resolves in a few days, although it does occasionally last a week or two.

Another “heady” product of the birthing process is caput succedaneum. Sometimes referred to as “caput” for short, this is a collection of fluid just under the skin of the scalp. It crosses the sutures, or spaces between the unfused bones of the skull, and can occasionally have a slightly bruised appearance. This generally resolves in a few days.

More obvious bruising is present in a condition called cephalohematoma. This generally shows up a few hours after birth and is due to slight bleeding between the skull bone and its outer membrane, or periosteum. This usually involves one skull bone at a time and doesn’t cross the suture line. (In practice, differentiating a caput from a cephalohematoma by looking at the sutures is not always easy, but since they’re both benign conditions, it usually isn’t that important.)

Cephalohematoma also resolves, but it takes a little longer—say, weeks or months. Occasionally, it turns hard, almost like the baby is growing new skull. This is due to calcium deposits. But ultimately, these are absorbed by the body, producing a normal kid head!

The major concern with a cephalohematoma is jaundice over the first few days of life. This happens because the area contains blood, which is broken down into that jaundice chemical bilirubin. Your baby’s provider will keep a close eye on this and possibly order a blood test or two for this condition.

The provider will also look for signs of one of the more concerning causes of a head bump—rupture of a larger blood vessel, for example. More serious causes than those we’ve talked about are very rare, however, and can usually suspected based on a more concerning appearance of either the head or the baby. Molding, cephalohematoma and caput are normal variants—and great reasons for lots of “before and after” pics! 

Stan Sack
Dr. Stan Sack has 29 years’ experience as a primary care pediatrician in Massachusetts and Florida. A medical writer since 2015, he enjoys blogging on topics that are on parents’ minds but are covered less often in books and on websites. He lives in the Florida Keys with his family and enjoys healthy cooking, fitness activities and singing in his spare time.

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