Share this on:Copied!

As you cuddle your newborn, you may feel surprised to find a soft spot on their head. If you look closely, you might even notice the top of your baby’s head pulsating.

There’s no need to worry or panic; what you’re seeing is normal and serves a purpose. The fontanelles — these soft spots — allow for delivery and later brain growth to take place. And they eventually close, usually by your baby’s second birthday.

Here’s what you need to know about your baby’s fontanelles.

What Is a Fontanelle?

A fontanelle, otherwise known as a baby’s soft spot, is an area of the skull where the bones haven’t yet joined. It’s very slightly concave and firm to the touch.

Although people call a fontanelle a soft spot, it’s actually a tough membrane covered by skin. It only seems soft compared with the bones of the skull.

There are two fontanelles. The larger and more noticeable soft spot is the anterior fontanelle, located on the top of the head and shaped like a diamond.

The posterior fontanelle is smaller and at the back of your baby’s head. Its shape is more triangular.

Why Fontanelles Exist

Your baby has fontanelles because the skull bones haven’t yet fused at birth. Instead, tough connective tissue holds the bone plates together. The connective tissue allows for some flexibility and movement.

Because the bone plates can compress and even overlap, the baby’s head can squeeze through the narrow birth canal. Many babies born vaginally have a noticeably cone-shaped head right after birth. Delivering a baby with a completely rigid skull would be extremely difficult.

After the baby is born, the bone plates move back into place. But there are still two soft gaps — fontanelles — in the skull.

All babies have fontanelles, whether they had a vaginal or cesarean birth.

There’s another reason fontanelles exist. A baby’s brain grows rapidly in the first year of life, and the flexible soft spots on the baby’s head allow this growth to take place.

Will the Fontanelles Go Away?

Yes. As your baby grows, the skull bones will eventually fuse, and the soft spots will close up.

The posterior fontanelle fuses first. It disappears about six to eight weeks after birth.

The anterior fontanelle takes longer to go away. It usually closes when your baby is between 13 and 24 months old.

Talk to your doctor if your baby’s soft spots are taking unusually long to close. Your baby may have a slightly delayed timeline.

Less commonly, a soft spot that doesn’t close is a possible sign of another problem. Your child could have a growth problem, Down syndrome, or rickets, a condition that causes weak bones in children. (These conditions all have other symptoms as well.)

Touching Your Baby’s Fontanelles

Feeling a little nervous when handling a newborn baby is normal, especially as a first-time parent. Touching your baby’s fontanelles may even scare you.  And what happens if you hit a baby’s soft spot by accident?

Relax. A minor bump is unlikely to hurt the soft spot because the membrane covering the fontanelle is very tough.

You can gently hold your baby’s head, wash their hair, and use hoods and hats without worrying about hurting the fontanelle. Of course, you always want to take care to avoid accidents. But having said that, the fontanelle isn’t especially delicate.

Your doctor will check your baby’s soft spot for proper growth as part of a routine well visit.

An Unusual-Looking Soft Spot: When to Call the Doctor

A normal fontanelle feels soft and flat if you run your fingers over it. You may see or feel a light pulsing as the blood flows under it.

There are times, however, when your baby’s fontanelle could signal signs of trouble. Here’s when you should call the doctor.

Bulging fontanelle

A baby’s soft spot can bulge for several reasons. The fontanelle may bulge slightly if your baby is lying down, crying, or vomiting. But the soft spot should return to normal when your baby is calm and lifted into an upright position.

If the soft spot keeps bulging when your baby is upright, it’s a possible sign of a rare but serious condition.

A bulging soft spot is a possible symptom of:

• Brain abscess — A pus-filled swelling that can come from an infection elsewhere in the head or neck. It may occur after a head injury and can lead to brain and nerve damage.
• Cerebral hemorrhage — Bleeding in the brain (more common in premature babies). Complications include developmental delays and brain damage.
• Encephalitis — Swelling or inflammation of the brain, usually from an infection. It can lead to brain damage.
• Hydrocephalus — A buildup of cerebrospinal fluid (CSF) in the ventricles, or cavities, of the brain. This buildup can put pressure on the brain and lead to learning disabilities, vision problems, and epilepsy.
• Meningitis — An infection of the membranes that cover the brain. Complications include hearing and vision loss, as well as brain damage.

Note: Call the doctor immediately if your baby’s fontanelles look unusually swollen and they also have a fever or seem lethargic. These symptoms could signal a serious injury or illness.

Sunken fontanelle

If the soft spots look noticeably indented, your baby may have become dehydrated. (A normal fontanelle will look flat to very slightly concave.)

A sunken soft spot isn’t the only sign of dehydration. If your baby isn’t getting enough breast milk or formula, you may notice:

• Cool hands and feet.
• Dry mouth.
• Excessive sleepiness.
• Extreme fussiness.
• Few or no tears when crying.
• Fewer wet diapers than usual (less than six wet diapers per day).
• Floppy arms and legs.
• Not breastfeeding or taking a bottle.
• Sunken eyes.
• Vomiting or diarrhea.
• Wrinkled skin.

When in doubt, it’s always a good idea to call your pediatrician if you feel something is wrong with your baby. You know your child and their habits best.