Are you curious about that soft spot on your newborn’s head, known as the fontanelle? Well, you’re not alone – I get tons of questions about this from parents just like you. Let’s discuss what that soft spot is, its purpose, and what to look out for.

What is the Soft Spot (Fontanelle)?

The fontanelle is a gap between the bones of your baby’s skull. Newborns have two main fontanelles: the larger, diamond-shaped anterior fontanelle at the top, and the smaller, triangular-shaped posterior fontanelle at the back of the head.

What is the Purpose of the Soft Spot?

These soft spots are safe, normal, and are super important to your baby’s development because:

1. Ease of Birth: The soft spots make space for the bones of the head to shift during birth, allowing baby’s head to fit and move through the birth canal. In fact, those bones may overlap during delivery, causing molding and a temporary cone-shaped head.
2. Brain Growth: Your baby’s brain is growing rapidly, and the fontanelles ensure that they’re enough room for the brain to grow without being impeded by the bones of the skull.

Keeping an Eye Out: What’s Normal and What’s Not?

Normal Newborn Soft Spot:

1. Feel: Go ahead and gently touch the fontanelle–you won’t hurt your little one! The anterior fontanelle will usually feel soft and slightly indented.
2. Size: The anterior fontanelle is typically 3 to 4 cm long by 2 to 3 cm wide. But remember, every baby is different!
3. Closing Time: The posterior fontanelle is typically enclosed by bone by around 2-3 months, while the anterior fontanelle takes bout 9-18 months to fully close.

When to Call Your Doctor:

1. Sunken Spot: If the soft spot looks significantly dipped in, this can be a sign of dehydration.
2. Bulging Fontanelle: The soft spot may bulge slightly when baby cries or is pooping, which is normal. You may even see it pulsing with your baby’s heartbeat! But if the fontanelle seems swollen or bulging when your baby is calm and upright, it could signal a problem.
3. Unusual Size or Closure: If the fontanelle seems to be too big, too small, or is closing too late or too early, it’s best to get it checked out.
4. Other Symptoms: If baby has a bulging or sunken fontanelle as well as symptoms like fever, vomiting, or sleepiness, call your doctor.

Tips for Care and Handling

• Be Gentle: It’s a myth that touching the fontanelle will cause brand damage. So while the fontanelle seems delicate, it’s protected by a tough membrane. Still, be gentle and careful whenever you may need to touch the soft spot.
• Sleep Positions: Try to mix up how your baby lies down to sleep. Alternating the position in which baby’s head is placed while back sleeping. This can help prevent plagiocephaly–an asymmetric head shape where a helmet is necessary for correction.

Conclusion

Your newborn’s soft spot is a normal, functional part of your baby’s anatomy. Keep any eye on any significant changes in the fontanelle, but know that most changes are normal and a healthy part of your baby’s development.

References:

Davidson, M., Longon, M., and Ladewigh, P. (2012). Olds’ Maternal-newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition.

Hockenberry, M., Wilson, D. (2008). Wong’s Nursing Care of Infants and Children, Ninth Edition.

Positional plagiocephaly and sleep positioning: An update to the joint statement on sudden infant death syndrome. Paediatr Child Health. 2001 Dec;6(10):788-93. doi: 10.1093/pch/6.10.788. PMID: 20084156; PMCID: PMC2805995.