It seems there’s so much to worry about with a new baby.
This precious little being is suddenly in your care and seems so vulnerable.
One common concern for new parents is the ‘soft spot’ on the top of the baby’s head.
The name for this spot is the ‘fontanelle’ or ’fontanel’.
Concern about this area creates a lot of questions:
How careful do you need to be with this area?
What if your baby has a sunken fontanelle but no other symptoms of dehydration?
Is it normal to see a pulse in this space?
When will it close?
Keep reading to learn more about the amazing features of your baby’s skull and answers to these and other questions regarding fontanelles.
What is a fontanelle (soft spot)?
All infant skulls have several plates. The borders where these plates eventually fuse and harden are called suture lines.
There are several ‘soft spots’ or fontanelles on the newborn skull; these are the spaces where the suture lines cross.
The suture lines and fontanelles of the skull allow the bones to overlap and mold during their passage through the birth canal.
At birth, your baby’s brain is about 25% of the size of an adult brain. It doubles in size in the first year!
These gaps in the unfused bones of the baby’s skull allow for this rapid growth.
The normal newborn head
The shape of your newborn baby’s head depends on the position your baby was in during labor.
Babies who are born anterior are more likely to have a ‘conehead’ shape.
Infants who are anterior-positioned are born with their faces against the mother’s back. This is the optimal position for birth as it allows for the most molding of the head.
Although this molding can look quite dramatic it usually resolves within several hours after birth. By 24 hours of age, your sweet baby’s head shape will appear more normal.
Infants who are born breech (bum or feet first) or posterior have different head shapes than vertex (head-first) and anterior-positioned babies.
Posterior babies are born with their backs against the mother’s back – sometimes called “sunny-side up”.
Babies born by c-section can have less head molding depending on how far down in the pelvis they descended before birth.
The anterior fontanelle on the top of the head is the most prominent. This diamond-shaped space takes the longest to close. It is the spot most people refer to as the ‘soft spot’.
There is also a triangle-shaped fontanelle further toward the back of the head. This posterior fontanelle is much smaller and closes in the first few months of life.
Can I touch the top of my baby’s head safely?
Although this spot isn’t protected by the hard skull bones in an infant, it’s protected by a strong membrane and is open for important reasons. Don’t fret too much about it!
You can safely wash your baby’s hair and head, stroke his head, use a brush on his hair, and allow gentle touches from older siblings and friends. You can do all this without worrying about the site of the soft spots.
It’s recommended you touch the fontanelle gently and become familiar with how it is normally, so you’ll be more aware if something is out of the ordinary.
Normal fontanelle compared with sunken fontanelle
The normal anterior fontanelle is located about one third of the way back on the top of your baby’s head. It curves in a bit and feels firm to the touch.
A sunken fontanelle can be a sign of dehydration.
It would be accompanied by other symptoms such as:
- Dry lips
- Parched mouth
- Reduced number of wet diapers
- Concentrated urine
- Fewer tears when baby cries
- Loose, frequent stools (if dehydration is caused by diarrhea)
- Reduced number of dirty diapers (if dehydration is due to vomiting or low fluid intake)
- Cool or dry skin
- Sunken eyes.
A dehydrated baby might also show changes in behavior, such as fussiness and unusual sleepiness.
If your baby has any signs of dehydration you should contact your pediatrician as soon as possible. This is particularly important if your baby is ill and not keeping fluids down.
Sunken fontanelle, not dehydrated
Remember, normal fontanelle dips in a bit. It might look sunken but this doesn’t necessarily mean your baby is dehydrated.
If your baby doesn’t have any of the above symptoms of dehydration, is nursing and feeding regularly, and having 6-8 wet nappies in a day you can be assured this is normal.
Sunken fontanelle in a breastfeeding baby
It’s common to think a sunken fontanelle means dehydration. You might be tempted to give your infant water in order to keep him hydrated.
If your infant is exclusively breastfed and is under 6 months old it is not recommended to give water or any other fluids.
If your baby is sick or you are experiencing hotter weather, make sure you offer the breast more often.
In these circumstances, infants often want shorter, more frequent feeds, which will keep them hydrated.
Just follow your baby’s cues!
Sunken fontanelle when sitting up
You might notice a sunken fontanelle, or that your baby’s soft spot is more noticeable when he’s sitting up rather than lying down.
This is normal and simply due to gravity.
Sunken fontanelle after crying
It’s normal for the anterior fontanelle to bulge slightly during crying. If your baby has been upset and then has calmed down, it might seem as if the bulging fontanelle now appears sunken.
During hard bouts of crying the fontanelle can move up and down with the exertion of crying.
You might also see this movement if your baby is vomiting. Again, this is due to exertion.
A bulging or swollen fontanelle is a concern; it can be a sign of fluid or swelling in or around the brain.
If you see or feel a bulging fontanelle site when your child is calm or resting you should seek medical advice right away.
You might be able to see the soft spot pulsing from time to time – especially if your baby doesn’t have much hair.
Although this might be alarming, it’s completely normal.
Some parents advise putting a hat or bonnet on your baby’s head if the pulsing of a sunken fontanelle disturbs you.
When do the fontanelles close?
The presence of the soft spot is important to allow the baby’s skull to adjust for birth and to allow for the brain to grow after birth.
The larger anterior fontanelle begins to close as your baby becomes more mobile. This usually happens at around 6 months of age. By the time your baby is a busy toddler (around 18 months), you’ll no longer be able to feel it.
Rarely, babies have a condition called craniosynostosis. This means the plates of the skull close too soon. This can cause pressure or affect brain growth.
Fontanelles can also be larger than normal or they might not close at the appropriate time. This can be seen in children with Down syndrome or hypothyroidism.
When to worry about baby’s soft spot
The following signs might be cause for concern:
- Sunken fontanelle with symptoms of dehydration
- Bulging fontanelle
- Very large fontanelle
- Fontanelle that closes before the first year
- Fontanelle that stays open past 2 years of age
If you notice any of the above problems contact your healthcare provider.