Fontanelles: What Parents Need to Know About Baby's Soft Spots

Why does baby have soft spots (fontanelles) on their head, and how to care for them? Learn the answers to these questions about baby’s soft spots.

Why does baby have soft spots on their head, and how to care for them? When do baby’s soft spots usually close up? We answer parents’ most common questions about baby’s soft spots, also called fontanelles.

What are fontanelles (baby soft spots)?

Your baby will be born with two soft spots, or fontanelles, on their head.

  • The first one is called the anterior fontanelle, and that’s the diamond-shaped soft spot on the top of their head.
  • The second one is called the posterior fontanelle, and that’s the triangle-shaped soft spot at the back of their head. (You might not notice this one.)

Baby has soft spots, or fontanelles, on their head because their skull is still growing and developing.

Babies’ skulls are made up of several different soft bones (known as plates) that haven’t yet fused together.

The gaps where these skull plates haven’t yet fused together are baby’s soft spots.

This creates a flexible skull shape that’s important for two main reasons.

  • First, the flexible skull lets baby’s head pass through the birth canal without damaging their brain.
  • Second, the flexible skull leaves plenty of room for baby’s brain to grow over their first two years. Baby experiences rapid head and brain growth over their first two years, and the skull needs to be flexible to accommodate this.

Learn more about baby's fontanelles from Nurse Dani of Intermountain Moms:

How do I care for baby’s soft spots?

Baby’s soft spots may look very delicate. But baby actually has a thick membrane under their scalp, that keeps their brain protected.

As long as you touch baby’s soft spots gently, you won’t hurt baby. So don’t be afraid to gently touch baby’s soft spot.

It’s perfectly safe to brush their hair using a baby comb or brush, even over the soft spots.

It’s also safe to gently touch the soft spots when you hold baby.

And during bathtime, you’ll need to gently scrub their scalp --- including their soft spots --- to get rid of the flakes that build up. This helps prevent cradle cap.

The only thing to watch for is this --- don’t put pressure on baby’s soft spot.

And it’s always good to remind your other children, your family members and your friends to be gentle when touching baby, especially around their head.

What do normal fontanelles look like?

Knowing what baby’s soft spots are supposed to look like can help you determine what’s normal and when you should be concerned.

Normal soft spots:

  • Look flat --- not sunken, swollen, or bulging
  • Feel soft and flat, while curving slightly downward
  • May look raised or look “bulging” when baby vomits, cries, or is lying down --- but goes back to normal when baby is upright and is no longer vomiting or crying. (This is because crying and vomiting temporarily increase the pressure in baby’s skull.)

What if baby’s soft spot pulsates?

If baby’s soft spot pulses with their heartbeat, this is completely normal! As the heart moves blood through baby’s body, you can sometimes see this movement through baby’s soft spots, in time with their heartbeat. Don’t be concerned about a pulsating soft spot!

When should I be concerned about baby’s soft spots?

Here’s when you should be concerned about the appearance of baby’s soft spots:

Baby’s soft spot is sunken

If baby’s anterior fontanelle is sunken, this could be a sign that baby is dehydrated. Other signs of dehydration include a dry mouth, not enough wet diapers, irritability, and crying with no tears.

Baby dehydration is serious and requires immediate medical attention. If you suspect baby is dehydrated, call your pediatrician immediately.

Baby dehydration could be caused by feeding difficulties, overheating, a fever, vomiting, or diarrhea.

Baby’s soft spots stay bulging or swollen

If baby’s soft spots are bulging even when they are resting and not crying, this could indicate a problem. The same goes if baby’s soft spot is hard and swollen.

There could be swelling in baby’s brain, or too much fluid in their brain. Both of these conditions are very serious and require immediate medical attention. If baby’s soft spot is bulging, or hard and swollen, contact your pediatrician right away.

Baby hit their soft spot

If baby hits their soft spot, call your pediatrician immediately. They will need to make sure baby didn’t cause a head injury or concussion.

Baby may have a head injury if they hit their soft spot, are unwilling to feed, vomit or have seizures, start to cry nonstop, have trouble waking up, and/or have bloody eyes or a bloody nose.

A bulging or swelling soft spot, plus bruises behind the ears, could be a sign of a concussion. Call 911 immediately if baby shows these signs.

Baby doesn’t appear to have soft spots

In very rare cases, a baby’s skull plates fuse together too early, and that baby won’t have soft spots. This is caused by a condition called craniosynostosis. This condition may affect brain growth, and may require surgery to remedy.

At every checkup, your pediatrician will check to make sure baby has soft spots, and that the soft spots look healthy, for this and other reasons. It’s important to note, though, that some babies have soft spots that are difficult to feel or see, but that are still present.

When do the fontanelles usually close up?

Baby’s anterior fontanelle (the one on the top of the head) could close as early as 9 months of age, and will often close up by 18 months of age. It will almost always close up by 2 or 3 years of age.

The posterior fontanelle (on the back of the head) will usually close up far sooner, and you might not even notice it. On average, that soft spot will usually close between 1 and 3 months of age, and will almost always close by 6 months of age.

Every baby is different, though, so don't be concerned about how early or late the fontanelles close.

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