Baby Daily Life
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You’re holding your baby in your arms, everything is going perfectly well until you notice: you feel small soft spots on their skull… Don’t panic! This is completely normal. What are fontanelles? What are they for? Should they be protected?
Here’s everything you need to know!
What are a baby’s fontanelles?
With a baby in your arms, you’re never short of questions! Today’s topic: fontanelles. Let us reassure you right away: these little soft spots on your baby’s skull are perfectly normal!
At birth, a newborn’s skull is made up of five main bones. These bones are separated and connected by what we call cranial sutures.
In practice, the different parts of the skull are joined together by softer junction areas before fusing later during growth. In the meantime, before the skull bones fuse, you can feel these soft spots at the front and back of your baby’s head: these are what we call fontanelles.
There are six different ones (one for each junction area) but only two fontanelles can be directly felt.
➡️The anterior fontanelle: this is the largest of the six fontanelles and, as its name suggests, it is located at the front of the baby’s head. It has a diamond shape.
➡️The posterior fontanelle: triangular in shape, it is located at the back of the baby’s head and is much smaller than the anterior fontanelle.
What are infant fontanelles for?
Fontanelles have several important functions.
➡️First, they are essential on the day of birth. During a vaginal delivery, fontanelles allow your baby’s skull to pass more easily through the pelvis and then through the cervix. These soft areas give the skull some flexibility/adaptability.
➡️Later, fontanelles allow the brain to develop without lacking space in the skull (which remains “moldable” thanks to them). The skull size can therefore increase quite rapidly during the first three years.
➡️The appearance of fontanelles can also give an idea of your newborn’s state of health: while they are generally flat, they can sometimes appear bulging or sunken, indicating normal or elevated intracranial pressure, or dehydration.
➡️In addition, the speed at which fontanelles close can also indicate a health condition or a specific pathology, which can then be identified early.
When do a baby’s fontanelles close?
A newborn keeps their fontanelles for a while: in fact, the posterior fontanelle normally closes between 2 and 4 months of age, even though it is usually already very small at birth, while the anterior fontanelle closes between 9 and 18 months according to Health Insurance.
This is why, after birth, your doctor or pediatrician will regularly measure the head circumference of your baby and check the closure of the fontanelles. This examination is not invasive since it is simply done by feeling the fontanelle.
This way, they can ensure they do not close too early or too late and can detect a possible pathology at an early stage.
Want to learn more? Feel free to download the May app, where you’ll find plenty of resources to support and guide you throughout your journey as a new parent.
How do I know if my baby’s fontanelles are normal?
As we have seen, fontanelles are usually soft and flexible. If the fontanelles are neither bulging nor sunken, everything is fine.
When your baby is calm, they may move in rhythm with the heartbeat. When your baby cries or even coughs, they can temporarily bulge—no need to worry.
➡️However, sunken fontanelles often indicate dehydration.
It is not unusual for fontanelles to be a little more sunken when your baby is resting. On the other hand, if they remain sunken while your baby is awake, consult quickly. If it’s feeding time and your baby is otherwise fine, wait until after they’ve eaten—the fontanelle should return to normal!
➡️Conversely, bulging fontanelles can indicate elevated intracranial pressure. Do not hesitate to seek urgent medical care. This can indicate conditions such as fluid buildup (hydrocephalus), meningitis, a tumor, or hemorrhage.
❗In any case, if you notice a change or an unusual texture by sight or touch, contact a healthcare professional to make sure everything is fine.
What should I do if my baby’s fontanelles are sunken?
As we have seen, sunken fontanelles are very often a sign of dehydration. Dehydration can quickly endanger the life of an infant (water represents up to 80% of a newborn’s weight): it is therefore a case that requires urgent consultation.
❗As a reminder, the main signs of dehydration in a child (besides sunken fontanelles) are:
- Your baby sleeps a lot,
- They have lost weight (more than 5%),
- They urinate very little,
- Their mouth (tongue and lips) is dry,
- They cry but produce no tears,
- They look pale,
- They have sunken eyes.
Water loss can happen very quickly in infants, so it is important to be vigilant before 12 months of age (and even afterwards!).
To prevent dehydration in your baby, you can give them an oral rehydration solution (ORS). These are available in pharmacies, with or without a prescription. We recommend always keeping a few sachets at home just in case.
Are there precautions to take to protect a baby’s fontanelles?
Even though they seem fragile compared to the rest of the skull, fontanelles are stronger than they look. In fact, they are even less likely to break than a bone.
Of course, this doesn’t mean you should press down hard on them, but there is no need for your baby to wear a helmet either. It is also important to wash your baby’s entire head, including the fontanelles. You can massage this area with shampoo without any problem, rinse, and brush over it.
Good to know: Your baby may have cradle cap. Infant seborrheic dermatitis is a common skin condition, linked to an excess of oily secretions on the scalp. These patches usually appear before the age of 6 months (often as early as the second week of life) in an otherwise healthy baby. The good news is, they are neither contagious nor uncomfortable. However, it is a good idea to remove them gradually, to make hair growth easier and avoid infection.
As we have seen, fontanelles are a fascinating feature of an infant’s skull. They gradually close and can provide valuable information about your baby’s health.
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Photo: Demkat
This text was translated from French by an artificial intelligence. The information, advice, and sources it contains comply with French standards and may therefore not apply to your situation. Make sure to complement this reading by visiting the May US/UK app and consulting the healthcare professionals who are supporting you.
