When to Worry About Baby’s Soft Spot: Normal vs Concerning Signs

Every newborn has soft spots on their head, and while they serve an essential purpose, they can be a source of significant anxiety for parents. Knowing when to worry about baby’s soft spot helps you distinguish between normal variations and signs that something may need medical attention. These soft areas, called fontanelles, are a normal and important part of infant development.

Understanding what a healthy fontanelle looks and feels like, and what changes signal a problem, gives you the confidence to care for your baby without unnecessary fear. This guide covers what parents need to know about baby’s soft spot, from basic anatomy to the specific warning signs that warrant a call to your pediatrician or, in some cases, emergency care.

What Are Fontanelles and Why Do Babies Have Them?

Fontanelles are gaps between the bones of a baby’s skull where the bones have not yet fused together. A newborn’s skull is made up of several separate bone plates connected by flexible, fibrous tissue called sutures, according to MedlinePlus. The fontanelles are the wider spaces where multiple sutures meet.

Babies have two main fontanelles:

• Anterior fontanelle: Located on the top of the head toward the front. It is diamond-shaped and typically measures roughly 1 to 3 centimeters at birth, though it can be larger. This is the soft spot most parents notice and worry about. It usually closes between about 12 and 18 months of age but can take up to around 24 months.
• Posterior fontanelle: Located at the back of the head where the skull bones meet. It is much smaller (often around half a centimeter) and triangular. It typically closes by about 2 to 3 months of age.

Fontanelles serve two critical purposes:

1. Birth: They allow the skull bones to shift and overlap during delivery, enabling the baby’s head to pass through the birth canal.
2. Brain growth: They provide room for the brain to grow rapidly during the first years of life. The brain grows dramatically during this period, and rigid, fully fused skull bones would restrict that growth.

What a Normal Soft Spot Looks and Feels Like

A healthy anterior fontanelle has these characteristics:

• Flat or slightly curved inward when the baby is calm and upright.
• Firm but yielding to gentle touch, similar to pressing on a firm rubber ball.
• May pulsate visibly: You can often see a gentle pulsation that corresponds to the baby’s heartbeat. This is completely normal and simply reflects blood flow near the surface.
• May bulge slightly when the baby cries, strains, coughs, or lies down flat. This is temporary and normal as long as the fontanelle returns to its usual position when the baby is calm and upright.

You can safely touch, wash, and gently brush over the fontanelle during normal care. Despite feeling vulnerable, the soft spot is covered by a tough membrane that protects the brain, so normal handling, bathing, and hair care will not damage it.

When to Worry About Baby’s Soft Spot: Warning Signs

While most fontanelle variations are normal, certain changes can indicate serious conditions. Here is when to worry about baby’s soft spot. The two changes to know best are a bulging fontanelle and a sunken fontanelle.

Bulging Fontanelle (Possible Increased Pressure — Can Be an Emergency)

A fontanelle that is persistently swollen, raised above the level of the surrounding skull bones, or feels tense and firm even when the baby is calm and upright may indicate increased pressure inside the skull (increased intracranial pressure). This is one of the most important warning signs to recognize, and when it comes with fever, vomiting, drowsiness, or a change in behavior, it can be a medical emergency.

Possible causes of a bulging fontanelle include:

• Meningitis: Infection of the membranes surrounding the brain and spinal cord. Additional symptoms can include fever, irritability, poor feeding, lethargy, a stiff body, and a high-pitched cry. This is an emergency.
• Encephalitis: Inflammation of the brain, often caused by a viral infection.
• Hydrocephalus: A buildup of cerebrospinal fluid in the brain, which may be accompanied by a rapidly increasing head size, vomiting, and a downward “sunsetting” gaze of the eyes.
• Intracranial bleeding or other causes of raised pressure.

According to the Mayo Clinic, a persistently bulging fontanelle, especially when accompanied by fever, vomiting, irritability, or lethargy, requires immediate medical evaluation. Do not wait to see if it passes.

Sunken Fontanelle (Often Dehydration — Seek Urgent Care)

A fontanelle that appears noticeably depressed or concave, creating a visible dip in the top of the baby’s head, most commonly indicates dehydration. This is an important sign that healthcare providers check during infant examinations.

A sunken fontanelle combined with these symptoms strongly suggests dehydration:

• Fewer wet diapers than usual
• Dry mouth and lips
• No tears when crying
• Sunken eyes
• Lethargy or decreased activity
• Recent vomiting, diarrhea, or poor feeding

Dehydration in an infant can worsen quickly. While mild cases may improve with careful feeding (breast milk, formula, or an oral rehydration solution if advised by your clinician), a significantly sunken fontanelle or any sign of moderate-to-severe dehydration warrants urgent medical attention, as the baby may need evaluation and possibly intravenous fluids.

Early Closure (Craniosynostosis)

If the fontanelle closes much earlier than expected, it may indicate craniosynostosis, a condition in which one or more skull sutures fuse prematurely. Signs that the fontanelle may be closing too early include:

• The soft spot feels hard or is no longer palpable well before it typically closes
• An unusual head shape develops (asymmetry, elongation, or flattening)
• A raised, hard ridge forms along one or more suture lines
• Head circumference is not growing as expected on the growth chart

Craniosynostosis may require surgical correction to allow proper brain growth, and early diagnosis is associated with better outcomes. Your pediatrician evaluates head shape and sutures at well-child visits.

Late Closure

A fontanelle that remains widely open beyond about 18 to 24 months may be associated with:

• Hypothyroidism
• Rickets (vitamin D deficiency)
• Down syndrome
• Hydrocephalus
• Certain skeletal disorders

Your pediatrician monitors fontanelle closure at regular well-child visits and will investigate if closure is significantly delayed.

Unusually Large Fontanelle

Fontanelle size varies among infants, but an anterior fontanelle that is unusually large may sometimes be associated with conditions such as hypothyroidism, Down syndrome, or skeletal abnormalities. Your pediatrician will assess fontanelle size in the context of your baby’s overall health and development rather than in isolation.

What to Do If You Notice Changes

If you observe concerning changes in your baby’s soft spot, follow these steps:

1. Stay calm. Many fontanelle variations are temporary and benign.
2. Check the baby’s position. A fontanelle may look different when the baby is lying down, crying, or straining. Assess it with the baby calm and upright.
3. Look for other symptoms. A concerning fontanelle finding combined with fever, vomiting, lethargy, poor feeding, or behavioral changes is far more significant than a fontanelle change alone.
4. Contact your pediatrician — or emergency services for red flags. Describe what you see, when you noticed it, and any other symptoms. For a bulging fontanelle with fever or lethargy, or signs of significant dehydration, do not wait for a routine appointment.

Protecting Baby’s Soft Spot

While fontanelles are more resilient than they appear, taking reasonable precautions makes sense:

• Support your baby’s head and neck when holding and carrying them
• Be gentle when washing and brushing the baby’s hair over the fontanelle
• Avoid placing heavy objects near the baby’s head
• Use a firm, flat sleep surface as recommended by the AAP for safe sleep
• Ensure siblings and other children understand the need for gentle handling
• Use hats or shade for sun protection rather than pressing anything firmly against the head

When to See a Doctor

Frequently Asked Questions

Can I hurt my baby by touching the soft spot?

No, gentle touching will not hurt your baby. The fontanelle is covered by a tough, protective membrane that shields the brain. Normal handling during bathing, hair care, and cuddling is safe. You should avoid pressing forcefully on the fontanelle or allowing sharp objects near it, but routine care poses no risk.

Why does my baby’s soft spot pulsate?

The visible pulsation you see in the fontanelle is caused by blood flowing through arteries near the brain’s surface. The pulse matches the baby’s heartbeat and is completely normal. It is simply more visible in infants because the skull bones have not yet closed over this area. The pulsation itself is not a cause for concern.

What does it mean if the soft spot bulges when my baby cries?

Temporary bulging during crying, straining, coughing, or vomiting is normal. When a baby bears down, pressure in the chest and abdomen briefly rises, causing the fontanelle to bulge. This should settle within seconds of the baby calming down. A fontanelle that remains bulging when the baby is calm and upright is the scenario that requires medical evaluation.

At what age does the soft spot close?

The posterior (back) fontanelle typically closes by about 2 to 3 months of age. The anterior (front) fontanelle, which is larger and more noticeable, usually closes between about 12 and 18 months but can remain open up to around 24 months. The timing varies among infants. Your pediatrician tracks closure at regular well-child visits.

Should I worry if my baby’s soft spot is bigger than other babies’?

Fontanelle size varies naturally among infants. A larger fontanelle alone is usually not a concern, especially if your baby is developing normally, feeding well, and meeting milestones. However, a fontanelle that seems exceptionally large, or is growing larger over time, should be evaluated by your pediatrician to rule out conditions such as hypothyroidism or hydrocephalus.

Is a bulging soft spot always an emergency?

Not always — a brief bulge while crying is normal. The concerning situation is a fontanelle that stays bulging, tense, or firm when your baby is calm and upright, especially alongside fever, vomiting, lethargy, or a high-pitched cry. In that case, treat it as an emergency and seek care immediately.

Practical Takeaway

Understanding when to worry about baby’s soft spot gives you the knowledge to confidently care for your infant while recognizing genuine warning signs. A flat, slightly pulsating fontanelle that may bulge briefly during crying is entirely normal. The key red flags are a persistently bulging fontanelle (especially with fever or lethargy, which can signal increased pressure in the brain), a significantly sunken fontanelle (suggesting dehydration), and abnormally early or late closure. Regular well-child visits allow your pediatrician to monitor fontanelle development, and you should never hesitate to reach out with concerns between visits. For more on health conditions and when to seek care, explore our medical conditions guide.

Sources

• American Academy of Pediatrics (AAP) — HealthyChildren.org: fontanelles and safe sleep (healthychildren.org)
• Mayo Clinic — infant fontanelle, dehydration, and meningitis information (mayoclinic.org)
• Cleveland Clinic — fontanelles (soft spots) overview (clevelandclinic.org)
• MedlinePlus / NIH — fontanelles and infant skull development (medlineplus.gov)
• Nationwide Children’s Hospital — craniosynostosis and hydrocephalus patient information (nationwidechildrens.org)