My Baby's Soft Spot Is Still Open
The short answer
The anterior fontanelle normally closes between 9 and 18 months, but some healthy babies' fontanelles remain open until 24 months. A fontanelle that is still open beyond 18 months should be evaluated, as it can sometimes indicate conditions like rickets, hypothyroidism, or other causes. However, many late-closing fontanelles are simply a normal variant.
Parents everywhere have the same worry. You are doing the right thing by looking into it.
By Age
What to expect by age
Some fontanelles are beginning to close, but many are still open. This is within normal range. Your pediatrician will check the fontanelle at every visit and is monitoring for normal closure.
The fontanelle may be getting smaller or may still be clearly open. Both are within the normal range. Your pediatrician will check if it is getting smaller over time.
If the fontanelle is still open, your pediatrician may monitor more closely. It may still close normally, but if it is large, blood tests to check vitamin D levels, thyroid function, and calcium may be ordered.
An open fontanelle at this age warrants evaluation. Common treatable causes include vitamin D deficiency/rickets and hypothyroidism. If your child is otherwise developing normally, the cause is often easily correctable.
What Should You Do?
When to take action
- The fontanelle is getting progressively smaller.
- Your baby is developing normally.
- Head growth is normal.
- Your baby is under 18 months.
- The fontanelle is still open after 18 months.
- The fontanelle seems to be getting larger.
- The fontanelle is bulging or tense.
- Bulging fontanelle with vomiting, fever, or lethargy.
- Fontanelle with signs of increased intracranial pressure.
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 Physical Concerns
My Baby's Soft Spot Is Closing Early
The anterior fontanelle (soft spot) typically closes between 9 and 18 months, though some babies' fontanelles close as early as 3 months without any problem. Early closure is only concerning if it restricts brain growth (craniosynostosis). Your pediatrician monitors head growth and fontanelle size at every visit.
My Baby's Head Is Growing Too Fast
Head circumference is monitored at every well visit because it reflects brain growth. Crossing upward percentile lines in head growth can indicate benign familial macrocephaly (runs in families) or, rarely, increased intracranial pressure. Your pediatrician will evaluate the pattern, fontanelle, and development to determine if further investigation is needed.
My Baby Seems to Use One Side More Than the Other
Babies should use both sides of their body fairly equally during the first 18 months of life. While slight preferences can be normal, a consistent pattern of favoring one side - using one arm much more than the other, crawling with one leg dragging, or turning the head predominantly one way - should always be discussed with your pediatrician. Early identification of asymmetry leads to the best outcomes.
My Baby Only Army Crawls
Army crawling (also called commando crawling) is a completely valid and normal way for babies to move. Many babies army crawl for weeks or even months before transitioning to hands-and-knees crawling, and some skip hands-and-knees crawling entirely. What matters is that your baby is independently mobile and exploring their environment.
One Side of My Baby's Body Moves Differently
Babies should generally use both sides of their body equally. If one side consistently moves differently, is weaker, stiffer, or less coordinated, this warrants evaluation. Asymmetric movement can indicate hemiplegia (cerebral palsy affecting one side), brachial plexus injury, or other neurological conditions that benefit from early therapy.
My Baby Crawls Unevenly
While some variation in crawling patterns is normal, consistently favoring one side or dragging one limb while crawling warrants attention. Babies should use both arms and both legs relatively equally when crawling. Persistent asymmetry could indicate muscle tone differences, hip issues, or neurological concerns that benefit from early evaluation.