Pulsing Soft Spot (Fontanelle) in Newborns
The short answer
A pulsing or throbbing soft spot (fontanelle) on your newborn's head is completely normal. The pulsation you see is the heartbeat transmitted through the blood vessels beneath the thin membrane covering the fontanelle. This is a reassuring sign that your baby's circulatory system is functioning well. The fontanelle should be flat or slightly concave when your baby is calm and upright.
Thousands of parents search for this exact thing. You are not alone.
By Age
What to expect by age
The anterior fontanelle (the larger soft spot on top of the head) and posterior fontanelle (the smaller one toward the back) are normal openings between the skull bones. The visible pulsation is your baby's heartbeat transmitted through blood vessels beneath the fontanelle membrane. This is completely normal and expected. A normal fontanelle is flat or slightly concave when baby is calm and upright. It may bulge slightly when baby cries or strains, which is also normal.
The posterior fontanelle typically closes by 2-3 months. The anterior fontanelle remains open and may continue to show visible pulsation, which remains normal. Continue to be aware of the fontanelle's appearance: it should remain soft and flat when your baby is calm.
The anterior fontanelle remains open and pulsation may still be visible. This is normal. The fontanelle will gradually become smaller as the skull bones grow together. It typically closes between 9-18 months of age.
The anterior fontanelle is still open and may begin to gradually close. Pulsation may be less visible as the opening decreases in size. Complete closure typically occurs between 12-18 months. Your pediatrician checks the fontanelle at each well-child visit.
What Should You Do?
When to take action
- Visible pulsation of the soft spot that matches your baby's heartbeat
- Fontanelle that is flat or slightly concave when baby is calm and upright
- Slight bulging of the fontanelle when baby cries or strains that resolves when calm
- Both the pulsation and the soft spot itself are present and expected
- The fontanelle appears to be closing very early (before 6 months) or very late (after 18 months)
- You notice the fontanelle seems unusually large or small
- You are unsure whether the fontanelle appearance is normal
- A persistently bulging or tense fontanelle when baby is calm and upright, which could indicate increased intracranial pressure from infection (meningitis) or hydrocephalus
- A significantly sunken fontanelle, which can be a sign of dehydration, especially if baby is also feeding poorly or has fewer wet diapers
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
Worrying about your baby means you care. That is a good thing.
Related Medical Concerns
Cone-Shaped Head After Vaginal Birth (Head Molding)
A cone-shaped or elongated head after vaginal birth is very common and completely normal. It is called head molding and occurs because the bones of your baby's skull are not yet fused, allowing them to overlap and shift to fit through the birth canal. Your baby's head will round out naturally within a few days to weeks.
I'm Worried About Craniosynostosis
Craniosynostosis occurs when one or more of the fibrous joints (sutures) between a baby's skull bones close prematurely, affecting head growth and shape. It occurs in about 1 in 2,000-2,500 births. While it requires surgical treatment, outcomes are generally excellent when diagnosed and treated early. Not all abnormal head shapes are craniosynostosis - positional plagiocephaly is far more common.
My Baby's Head Shape Looks Abnormal
Many babies develop temporary head shape irregularities that are completely normal. A cone-shaped head from vaginal delivery reshapes within days. Mild positional flattening (plagiocephaly) from sleeping on the back is very common and usually improves with repositioning and tummy time. However, head shape changes involving ridges, a persistently bulging fontanelle, or rapid head growth changes should be evaluated to rule out craniosynostosis.
Achondroplasia (Dwarfism) in Babies
Achondroplasia is the most common form of short-limbed dwarfism, affecting about 1 in 15,000 to 40,000 births. It is caused by a mutation in the FGFR3 gene and is usually apparent at birth with characteristic features including short limbs, a larger head, and a prominent forehead. Intelligence is normal. With monitoring for specific complications and supportive care, children with achondroplasia lead full, active, and independent lives.
Adenoid Hypertrophy and Breathing
Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.
How to Advocate for Your Child's Needs
You know your child better than anyone, and your observations matter. If you feel something is not right with your child's development or health, you have every right to ask questions, request evaluations, and seek second opinions. Advocating for your child is not being difficult - it is being a good parent.