Baby Soft Spot (Fontanelle): What’s Normal and When It Closes

A baby soft spot, or fontanelle, is a normal gap between the bones of the skull. It lets the head mold during birth and gives the brain room to grow, and most babies have two you can feel. The small one at the back usually closes by 1 to 2 months, while the larger one on top typically closes between 7 and 19 months. It’s tougher than it looks, so gentle touching, washing, and brushing won’t hurt it. Two changes need prompt medical attention, a soft spot that looks sunken, or one that stays firm and bulging while your baby is calm and upright.

What a Baby Soft Spot Actually Is

A fontanelle is a space where the skull bones haven’t joined yet, covered by a thick, tough membrane. It isn’t a hole, and it isn’t fragile in the way the name suggests. That membrane protects the brain during everyday handling, feeding, and bath time.

The gap has two jobs. During birth, it lets the skull bones overlap slightly so the head can fit through the birth canal. After birth, it gives the skull room to expand while the brain grows very quickly, roughly doubling in size over the first year. Once that fastest growth slows down, the bones gradually knit together and the soft spot closes.

How Many Soft Spots Does a Baby Have?

A newborn has six fontanelles, though you’ll only notice two of them.

The other four sit along the sides of the skull. They’re small, close early, and are rarely felt through your baby’s hair.

When Does a Baby Soft Spot Close?

The back one closes first, and the top one takes much longer.

The range for the top soft spot is wide, and that’s expected. According to the American Academy of Family Physicians, the median closure age is 13.8 months. Only about 1% close by 3 months, around 38% have closed by the first birthday, and about 96% by the second. Boys tend to close a little earlier than girls. The size of the soft spot at birth doesn’t predict when it will close.

Premature babies often close later than this range, so pediatricians track them by adjusted age rather than birth date.

Is It Safe to Touch a Baby Soft Spot?

Yes. Normal handling won’t hurt your baby, and you don’t need to avoid the area.

Hair Washing and Cradle Cap

You can shampoo right over the soft spot with normal, gentle pressure. If cradle cap sits on top of it, which is common, a soft brush is still safe to use, since gentle brushing puts no meaningful pressure on the brain. If you’re choosing one, see whether cradle cap brushes actually work.

Hats, Carriers and Car Seats

Hats, headbands, baby carriers, and car seats don’t press on the soft spot in any way that matters. Kisses, cuddles, and a sibling gently patting the baby’s head are fine too.

When a Baby Soft Spot Injury Is a Concern

An injury doesn’t come from touching. The real risk is a fall or a blow to the head. If your baby falls and the soft spot bulges afterward, or they vomit, seem unusually sleepy, or won’t stop crying, get emergency care.

Why Does My Baby’s Soft Spot Pulse?

A gentle pulsing on the soft spot is your baby’s heartbeat. With no bone over that area, the pulse of blood vessels near the surface becomes visible, especially when your baby is calm. It can look strange the first time you notice it, but it’s completely normal.

What If the Soft Spot Isn’t Pulsing?

That’s normal too. The pulse is often faint, and lighting, your baby’s position, and their hair all affect whether you can see it. A soft spot you never see pulsing, in a baby who is feeding and growing well, isn’t a sign that anything is wrong.

Bulging Soft Spot: Normal or Not?

A soft spot can bulge for a moment when your baby cries, coughs, vomits, strains during a bowel movement, or lies down. Pressure inside the head rises briefly, and the soft spot puffs out. Once your baby is calm and upright, it should settle back to flat or curving slightly inward.

A soft spot that stays firm and bulging while your baby is calm and upright is different. MedlinePlus, the US National Library of Medicine’s health site, says a truly bulging fontanelle needs emergency care right away, especially with fever or unusual sleepiness. It can be a sign of raised pressure around the brain, such as from an infection like meningitis or a buildup of fluid.

Sunken Soft Spot: A Sign of Dehydration

A soft spot that looks clearly caved in, rather than just flat, is most often a sign that your baby is low on fluids. It rarely shows up alone. Look for fewer wet diapers, a dry mouth, crying without tears, and unusual sleepiness. MedlinePlus notes that a sunken fontanelle can be a medical emergency, so call your pediatrician right away rather than waiting to see if it improves. For the full checklist of warning signs, see our guide to dehydration in a newborn.

When to Get Help for Your Baby’s Soft Spot

When the Soft Spot Closes Too Early or Too Late

Early closure of the skull seams is called craniosynostosis. It can limit room for the brain to grow and often changes the shape of the head. You can’t diagnose it by feel at home. Your pediatrician watches for it by checking head shape and measuring head circumference at every visit.

Late closure, where the top soft spot is still open well past the second birthday, is usually just normal variation. Sometimes it’s linked to conditions such as congenital hypothyroidism, rickets, achondroplasia, or Down syndrome, which is why doctors keep an eye on it.

Size varies widely too. The American Academy of Family Physicians reports that the top soft spot measures about 0.6 to 3.6 centimeters across at birth, with an average of about 2.1 centimeters, and tends to be larger in Black infants. A small soft spot and a large one can both be completely healthy.

Occasionally a baby has an extra, smaller gap between the two main soft spots, sometimes called a third fontanelle. On its own, it usually means nothing, though a doctor may note it during an exam.

What Your Pediatrician Checks

At well-child visits in the first two years, your pediatrician will gently feel the soft spot and measure your baby’s head circumference, then plot it on a growth chart. Together, these show whether the skull is growing at a healthy rate and whether the soft spots are closing on a reasonable timeline.

The open soft spot is useful to doctors in another way too. Because there’s no bone over it, an ultrasound probe placed on the soft spot can show the brain underneath. That lets doctors check a young baby for bleeding or fluid buildup without a CT scan or sedation.

This article is for general information only. Every baby is different, and it can’t replace advice from a doctor who has examined your child. If you’re worried about your baby, contact your pediatrician or emergency services right away.