It can be alarming for parents when they notice that their baby’s soft spot, or fontanelle, appears to be sunken in. However, in most cases there is no cause for concern. Here is an overview of what the fontanelles are, what can cause them to appear sunken, and when you should contact your pediatrician.
What are Fontanelles?
Fontanelles are the soft spots on a baby’s head where the skull bones have not yet fused together. There are several fontanelles, but the two main ones are:
- The anterior fontanelle – located on the top of the head towards the front
- The posterior fontanelle – located towards the back of the head
These fontanelles allow the skull to flex during childbirth and also enable rapid brain growth during the first year of life. Typically, the anterior fontanelle closes by 9-18 months and the posterior by 2-3 months.
Why Does my Baby’s Fontanelle Look Sunken?
There are a few reasons why your baby’s fontanelle may appear sunken at times:
- Dehydration – If your baby is not getting enough fluid, the fontanelle may sink inwards temporarily. This is because the brain rests on a fluid cushion, so when hydration levels drop, the brain drops downwards.
- Low muscle tone – Babies with low muscle tone or floppy muscle control can develop a sunken fontanelle when lying down as their head flattens against the mattress.
- Development – As your baby’s brain and skull develop, the fontanelle may look more pronounced at times. This is a normal part of growth.
- Sleeping position – The way your baby’s head is resting while asleep may cause temporary indentation of the soft spot.
In most cases, a sunken fontanelle will return to normal on its own once the temporary cause resolves. Be sure to point out any changes to your pediatrician, however.
When to Seek Medical Advice
While a sunken fontanelle is usually nothing to worry about, contact your doctor if you notice any of the following:
- The soft spot remains sunken for over 24 hours
- Your baby is showing signs of dehydration – fewer wet diapers, dry mouth, sunken eyes, etc.
- Your baby seems excessively sleepy, irritable or difficult to wake
- You notice bulging of the fontanelle
- The sunken area feels rigid rather than soft
- Your baby has a fever or other signs of illness
These signs can indicate an underlying issue requiring medical treatment. Possible causes include:
Dehydration
If your baby is not getting enough fluid, dehydration can occur and cause a sunken fontanelle. Offer more frequent breastfeeding or formula feeding to increase hydration.
Infection
Bacterial infections such as meningitis can cause swelling and irritation in the brain and tissues under the fontanelle. This results in a sunken appearance.
Low calcium levels
Calcium is essential for proper bone development. Low calcium can lead to a soft and sunken fontanelle.
Malnutrition
Lack of proper nutrients can affect development and cause sinking of the soft spot.
Decreased oxygen levels
A sunken fontanelle coupled with bluish skin can indicate a lack of oxygen. This requires emergency medical treatment.
Intracranial pressure issues
Increased pressure on the brain due to bleeding, tumors or hydrocephalus can compress the fontanelle inward.
Is it Normal for Soft Spot to Pulse?
It is completely normal to feel a pulsing sensation at your baby’s fontanelle. This pulse matches the rhythm of your baby’s heartbeat and indicates blood flow in the brain. Some movement in and out with breathing is also common. The fontanelle should feel firm yet flexible. Any rigidity could signify increased intracranial pressure.
How to Care for your Baby’s Fontanelle
To keep your baby’s fontanelle protected and healthy:
- Support head during feeding, diaper changes and carrying
- Avoid direct pressure on the fontanelle
- Use soft bedding in the crib
- Keep your baby well hydrated and fed
- Watch for signs of dehydration or malnutrition
- Keep your hands clean when touching the head
- Avoid exposing to cigarette smoke
- Follow vaccine schedule to prevent infections
When Does the Soft Spot Close?
Here is a table with average fontanelle closing timeframes:
| Fontanelle | Average Closing Timeframe |
|---|---|
| Anterior fontanelle | 9-18 months |
| Posterior fontanelle | 2-3 months |
However, there can be slight variations from these timelines since each baby develops at their own pace. Premature babies often have later fontanelle closure. If the soft spot remains open beyond 2 years old, consult your pediatrician to rule out any underlying conditions causing delayed fusion.
Does a Sunken Fontanelle Cause Long-Term Problems?
A temporarily sunken fontanelle does not cause any long-term issues for your baby. As long as the underlying cause is resolved, the fontanelle will return to its normal position. With prompt treatment of any infections, good hydration and nutrition, normal development continues.
However, an extremely sunken or rigid fontanelle could potentially affect development if intracranial pressure or oxygen levels are not quickly restored. Another complication could be misshaping of the skull bones if they fuse together while collapsed inward. But this would require the fontanelle to remain significantly sunken for an extended period.
As long as you seek prompt medical advice for any abnormal fontanelle appearance, you can rest assured your baby will not have any lasting effects.
Conclusion
Noticing your baby’s soft spot appearing sunken can certainly be alarming for any parent. However, in the majority of cases, it is a temporary and harmless occurrence. Making sure your baby remains well hydrated and nourished, along with following safe sleeping practices, can prevent the fontanelle from sinking. Always contact your doctor if the sunken fontanelle does not correct itself within 24 hours or your baby displays any other concerning symptoms. With attentive parenting and good medical care, your baby’s fontanelle should close on schedule without complications.