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 everything parents need to know about baby’s soft spot, from basic anatomy to the specific warning signs that warrant a call to your pediatrician.

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. According to the NIH, a newborn’s skull is made up of several separate bone plates connected by flexible, fibrous tissue called sutures. 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 about 1 to 3 centimeters at birth, though it can be larger. This is the soft spot most parents notice and are concerned about. It usually closes between 12 and 18 months of age but can take up to 24 months.
• Posterior fontanelle: Located at the back of the head where the skull bones meet. It is much smaller (about 0.5 cm) and triangular. It typically closes by 2 to 3 months of age.

Fontanelles serve two critical purposes:

1. Birth: They allow the skull bones to overlap and compress 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 two years of life. The brain triples in size during this period, and rigid skull bones would restrict this 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 in the fontanelle that corresponds to the baby’s heartbeat. This is completely normal and simply reflects the blood flow through the brain’s blood vessels near the surface.
• May bulge slightly when the baby cries, strains, or lies down flat. This is temporary and normal as long as the fontanelle returns to its normal 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. 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:

Bulging Fontanelle

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 intracranial pressure. This is one of the most important warning signs to recognize.

Possible causes of a bulging fontanelle include:

• Meningitis: Infection of the membranes surrounding the brain and spinal cord. Additional symptoms include fever, irritability, poor feeding, lethargy, stiff neck, and a high-pitched cry.
• Encephalitis: Inflammation of the brain itself, often caused by viral infection.
• Hydrocephalus: Excess cerebrospinal fluid accumulation in the brain. May be accompanied by a rapidly increasing head circumference, vomiting, and “sunset eyes” (downward gaze).
• Intracranial hemorrhage: Bleeding within or around the brain.

According to the Mayo Clinic, a persistently bulging fontanelle, especially when accompanied by fever, vomiting, irritability, or lethargy, requires immediate medical evaluation.

Sunken Fontanelle

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 clinical 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

While mild dehydration can often be corrected with increased fluid intake (breast milk, formula, or oral rehydration solution), a significantly sunken fontanelle warrants medical attention, as the baby may need 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. The NIH reports that craniosynostosis occurs in approximately 1 in 2,000 to 2,500 births.

Signs that the fontanelle may be closing too early include:

• The soft spot feels hard or is no longer palpable before 6 months of age
• 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. Early diagnosis leads to better outcomes.

Late Closure

A fontanelle that remains widely open beyond 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

While fontanelle size varies among infants, an anterior fontanelle larger than 4 to 5 centimeters at birth may be associated with certain 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.

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 versus sitting up. Assess the fontanelle with the baby in an upright, calm position.
3. Look for other symptoms. A concerning fontanelle finding combined with fever, vomiting, lethargy, or behavioral changes is more significant than a fontanelle change alone.
4. Contact your pediatrician. Describe what you are seeing, when you noticed it, and any other symptoms. Your doctor can advise whether an in-office visit, urgent care, or emergency evaluation is appropriate.

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 called the dura mater, which shields the brain. Normal handling during bathing, hair care, and cuddling is perfectly 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 the 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 is not a cause for concern.

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

Temporary bulging during crying, straining, or vomiting is normal. When a baby cries or bears down, the increased pressure in the chest and abdomen temporarily raises intracranial pressure, causing the fontanelle to bulge. This should resolve 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 2 to 3 months of age. The anterior (front) fontanelle, which is the larger and more noticeable one, usually closes between 12 and 18 months but can remain open up to 24 months. The timing of closure varies among infants and across ethnic groups. 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 like hypothyroidism or hydrocephalus.

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), 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 information on health conditions and when to seek care, explore our medical conditions guide.