Why Is The Soft Spot Pulsing? When To Panic And When It’s Totally Normal

Before we can talk about the pulsing, let’s chat about what the soft spot actually is. It’s not just a delicate, unprotected area. It’s a marvel of human engineering designed to help your baby make their grand entrance into the world and to accommodate their incredible brain growth over the first year of life.

These soft spots are officially called fontanelles. They are simply gaps between the bony plates of your baby’s skull. Because a baby’s skull isn’t one solid bone yet, these flexible gaps serve two crucial purposes:

1. Easing the Journey Through the Birth Canal: During a vaginal delivery, the skull plates can overlap slightly, temporarily changing the shape of the baby’s head to navigate the narrow birth canal more easily. This is why many newborns have a slightly cone-shaped head for a day or two after birth! The fontanelles make this possible.
2. Making Room for a Growing Brain: A baby’s brain grows at an astonishing rate, more than doubling in size during the first year alone. The fontanelles allow the skull to expand easily to make room for all that critical development.

Your baby actually has several fontanelles, but there are two you’re most likely to notice:

• The Anterior Fontanelle: This is the one you’re probably looking at right now. It’s the larger, diamond-shaped soft spot on the top of the head. It’s the one that pulses most noticeably and is the last to close, typically fusing shut anytime between 9 and 18 months of age.
• The Posterior Fontanelle: This is a much smaller, triangle-shaped spot at the back of the head. It’s often harder to find and usually closes much earlier, typically by the time your baby is 2 to 3 months old.

It’s important to remember that while they are called ‘soft spots,’ they aren’t gaping holes. They are covered by a very thick, durable membrane that provides plenty of protection for the brain underneath. So, you don’t need to live in fear of touching your baby’s head!

Okay, so now for the main event: the pulsing. Seeing movement on your baby’s head can feel instinctively wrong, but the reason for it is beautifully simple. The pulsing you see in the fontanelle is simply your baby’s heartbeat.

Think about it. You can feel your own pulse at your wrist or on your neck because an artery is running close to the surface of the skin. Every time your heart beats, it pushes a surge of blood through that artery, creating a little throb you can feel. It’s the exact same principle on your baby’s head.

The fontanelle is a unique spot where there isn’t a thick layer of bone separating the skin from the blood vessels that cover the brain. When your baby’s heart beats, it pumps blood through these vessels, and the pressure change causes the flexible membrane of the fontanelle to move slightly. You are literally seeing a reflection of their healthy, strong heartbeat.

The pulsing might be more or less noticeable at different times. You might see it more clearly when your baby is quiet and calm, or perhaps after they’ve been feeding. This variation is normal. Far from being a scary symptom, a gently pulsing fontanelle is a visible reminder of the life and vitality flowing through your little one. It’s a sign that their circulatory system is doing its job perfectly.

As a new parent, your ‘normal’ meter is still calibrating. So, let’s be very clear about what a healthy, normal fontanelle looks and feels like. If you observe the following, you can take a deep breath and relax—everything is likely just fine.

What’s Normal for a Fontanelle:

• A Rhythmic, Gentle Pulse: The pulsing should be calm and match the rhythm of your baby’s heartbeat. It should not be a frantic, violent throbbing.
• It Looks Flat: When your baby is held upright and is calm, the soft spot should appear relatively flat against their head. It shouldn’t be noticeably sunken or bulging.
• A Slight Curve Inward: It’s normal for the fontanelle to have a slight downward curve or feel a little soft and indented to the touch. It’s a ‘soft spot,’ after all!
• Temporary Bulging: You might notice the fontanelle bulge out for a moment when your baby is doing something that temporarily increases pressure in their head, such as:
  • Crying intensely
  • Vomiting or coughing
  • Lying down flat

The key here is that it’s temporary. Once your baby calms down, is picked up, or stops coughing, the fontanelle should return to its normal flat state within a few minutes. This temporary change is not a cause for concern.

Now we get to the most important part of our chat. While a pulsing soft spot is normal, certain changes to the fontanelle can be signs of serious medical issues that require immediate attention. Your parental intuition is powerful, so if something feels wrong, it’s always best to get it checked out. Here are the specific red flags to watch for.

A Note on Urgency: If you see a significantly sunken or bulging fontanelle, especially when accompanied by other symptoms like fever or extreme lethargy, this is not a ‘wait and see’ situation. Call your pediatrician’s office right away. If it’s after hours, follow their instructions for emergencies.

1. A Sunken Fontanelle

A fontanelle that looks noticeably sunken or dipped in—like a small crater on your baby’s head—can be a key sign of dehydration. This is especially true if your baby has also had vomiting, diarrhea, or has been feeding poorly. Dehydration in infants can become serious very quickly.

2. A Bulging or Tense Fontanelle

This is generally the most serious fontanelle-related red flag. A fontanelle that is visibly bulging outwards or feels firm, tense, or full to the touch—especially when your baby is calm and sitting upright—can be a sign of increased intracranial pressure (pressure inside the skull). This can be caused by serious conditions such as:

• Meningitis: An infection of the membranes surrounding the brain and spinal cord.
• Hydrocephalus: A buildup of fluid on the brain.
• Encephalitis: Inflammation of the brain itself.
• Head Trauma: Bleeding or swelling from an injury.

A bulging fontanelle is almost always accompanied by other signs of a very sick baby, such as a high fever, extreme irritability or a high-pitched cry, vomiting, or profound sleepiness. If you see a bulging fontanelle, seek medical care immediately.

Many new parents are so worried about the soft spot that they are afraid to touch their baby’s head at all! Let me reassure you: you don’t need to treat your baby like they’re made of glass. That membrane protecting their brain is tougher than you think. Normal, everyday care is perfectly safe.

Do:

• Touch Their Head Gently: You can stroke their head, cuddle them, and support their head and neck as you normally would.
• Wash Their Hair: It is perfectly safe to gently wash your baby’s scalp and hair, even over the fontanelles. Use a soft baby brush or your fingertips and be gentle, just as you would with the rest of their delicate skin.
• Use Car Seats and Baby Carriers: These are designed for safety and will not harm the fontanelle.
• Let Them Wear Soft Hats: A soft, breathable hat is fine and will not put any dangerous pressure on the soft spot.

Don’t:

• Press Down Firmly or Poke: There is never a reason to apply direct, firm pressure to the fontanelle. While gentle touching is fine, poking is not.
• Panic About Minor Bumps: Babies are wiggly! A light, accidental bump to the head is usually not a cause for alarm. The membrane and surrounding fluid provide excellent cushioning. However, if your baby has any significant fall or head injury, you should always contact your pediatrician for guidance.
• Be Afraid: The most important thing is to not let fear of the fontanelle stop you from cuddling, holding, and bonding with your baby. Your gentle, loving touch is essential for their development!