8 Month Baby Fontanelle in Back of Head

What Does It Mean If My Baby Has a Sunken Fontanelle?

Medically Reviewed by Marvin Resmovits, M.D.

Medical Review Policy

All What to Expect content that addresses health or safety is medically reviewed by a team of vetted health professionals. OurMedical Review Board includes OB/GYNs, pediatricians, infectious disease specialists, doulas, lactation counselors, endocrinologists, fertility specialists and more.

We believe you should always know the source of the information you're reading. Learn more about our editorial and medical review policies.

on May 1, 2020

Here's what you need to know if the soft spot on top of your baby's head appears sunken.

Back to Top

Your baby's sweet noggin is undoubtedly cute, but it can also — perhaps surprisingly — clue you in to one aspect of your baby's health. All it takes is a quick check of the top of your baby's head.

If you notice a significantly sunken soft spot on top, it could be a sign that baby isn't getting enough fluid.

What is a fontanelle or soft spot?

Your baby has two soft spots, or fontanelles, on his head. The larger of the two is located on the very top of the head. The second, smaller one is located toward the back of baby's head.

If you gently touch these areas, you'll notice that they aren't hard like the rest of baby's head (or skull). The reason? The fontanelles are spaces between skull bones. Their purpose is to give your little one's head the flexibility it needed to squeeze and mold itself to fit through the birth canal during delivery.

Soft spots serve an additional purpose after birth: They allow for the phenomenal growth your baby's brain is undergoing in the first year. The smaller, posterior fontanelle fuses together completely by 2 to 3 months. The top (or anterior) fontanelle starts to close at 6 months and will usually be completely fused together between 19 and 24 months.

What is a sunken fontanelle or sunken soft spot?

The anterior fontanelle normally appears flat and firm. Sometimes it can bulge slightly (such as when baby cries), and less often, it can appear to be concave, or sunken.

It's okay if it curves inward slightly to the touch. But if the soft spot is significantly sunken, it's usually a sign that your baby is dehydrated and needs to be given fluids immediately.

Signs of a sunken fontanelle or sunken soft spot

If baby's fontanelle on the top of his head isn't flat but rather dips inward, it means his fontanelle is sunken.

Continue Reading Below

Causes of a sunken fontanelle or sunken soft spot on baby's head

Your baby's fontanelle changes with his state of hydration. A well-hydrated baby will have a fontanelle that is flat and firm. If your baby isn't getting enough fluids and is dehydrated, his soft spot can start to appear sunken.

What can I do about my baby's sunken soft spot?

No need to worry if your baby's fontanelle seems slightly indented. But if your baby has a noticeably sunken soft spot, it's important that you give him additional fluids as soon as possible. If you're breastfeeding, nurse more often. If you're bottle-feeding, add in an additional few bottles.

When to call the doctor

A significantly sunken fontanelle, along with other signs of dehydration (such as dry diapers), warrants a call to the doctor right away.

Remember, there's no need to be overly concerned about your baby's fontanelle — or even to be overly protective of it — but if you notice that baby's soft spot appears very sunken, it's important that you contact your pediatrician right away.

From the What to Expect editorial team and Heidi Murkoff, author ofWhat to Expect When You're Expecting. What to Expect follows strict reporting guidelines and uses only credible sources, such as peer-reviewed studies, academic research institutions and highly respected health organizations. Learn how we keep our content accurate and up-to-date by reading our medical review and editorial policy.

• What to Expect the First Year, 3rd edition, Heidi Murkoff.
• National Institutes of Health, National Library of Medicine, MedlinePlus, Fontanelles – Sunken, March 2019.
• Cleveland Clinic, 5 Warning Signs From Your Baby's Soft Spot, February 2019.
• WhatToExpect.com, Baby's Soft Spot, November 2019.
• WhatToExpect.com, Spotting and Preventing Dehydration in Babies, April 2020.
• WhatToExpect.com, Soft Spots, Cradle Cap and Funny Shapes: All About Your Newborn's Head, November 2018.
• American Academy of Pediatrics, Your Baby's Head, June 2010.
• American Family Physician, The Abnormal Fontanel, June 2003.

8 Month Baby Fontanelle in Back of Head

Source: https://www.whattoexpect.com/first-year/newborns/sunken-fontanel-soft-spot/

Share this post