My Baby's Head Is Growing Too Fast
The short answer
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.
Parents everywhere have the same worry. You are doing the right thing by looking into it.
By Age
What to expect by age
Head growth is rapid in the first months, and some variation in growth rate is normal. If head circumference is crossing upward percentile lines, your pediatrician will check the fontanelle (soft spot), look for signs of increased pressure, and may order an ultrasound through the open fontanelle.
Head growth should follow a consistent percentile. If crossing upward, your pediatrician may measure both parents' head circumference (familial macrocephaly is very common and benign). If your baby is developing normally and the fontanelle is normal, monitoring may be all that is needed.
Continued rapid head growth crossing percentiles warrants investigation. An MRI or ultrasound may be ordered to evaluate for hydrocephalus or other conditions. However, many babies with large heads simply have familial macrocephaly with normal development.
Head growth typically slows after the first year. If head circumference remains disproportionately large but your child is developing normally, this is often benign. Continued monitoring is important.
What Should You Do?
When to take action
- One or both parents have large heads.
- Your baby is developing normally.
- The fontanelle is soft and flat.
- Head size stabilizes at a high percentile.
- Head circumference is crossing upward percentile lines.
- Head size is disproportionate to body size.
- The fontanelle seems full or bulging.
- Rapid head growth with vomiting, irritability, or lethargy.
- Bulging fontanelle with sunsetting eyes.
- Head growth acceleration accompanied by developmental regression.
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 Has a Large Head That Runs in the Family
Familial (benign) macrocephaly is the most common cause of a large head in babies. If one or both parents have large heads and your baby is developing normally, the large head is almost certainly an inherited trait. Your pediatrician will still monitor head growth to ensure it follows a consistent trajectory.
My Baby's Head Seems Too Big or Small for Their Body
Babies naturally have proportionally larger heads than adults - a baby's head is about 25% of their body length compared to 12% in adults. However, when head size is on a very different percentile from length and weight, your pediatrician will monitor and may evaluate for conditions like familial macrocephaly, nutritional issues, or genetic conditions.
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.