My Baby Has a Small Head That Runs in the Family
The short answer
Familial microcephaly (small heads running in the family) is a benign condition where a baby's head circumference is below average but the brain develops normally. If one or both parents have small heads and your baby is developing on track, the small head size is likely inherited and not a medical concern.
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By Age
What to expect by age
Your pediatrician will measure parental head circumferences to assess familial pattern. If your baby is developing normally and head growth is consistent (even if at a low percentile), familial microcephaly is the likely explanation.
Continued normal development with a consistently small head is reassuring. Your pediatrician monitors head growth at every well visit. If development is also delayed, further evaluation may be needed.
If your child is meeting developmental milestones with a consistently small head matching family pattern, no intervention is needed. Ongoing monitoring at well visits is sufficient.
Children with familial microcephaly develop normally and lead normal lives. The small head size is simply a genetic trait, much like having smaller feet or shorter stature.
What Should You Do?
When to take action
- Parent head sizes are also below average.
- Head is tracking consistently along a low percentile.
- Development is on track.
- Head growth is not decelerating.
- Head circumference is falling across percentile lines.
- Small head is combined with developmental delays.
- Head growth has stalled.
- Head growth is decelerating rapidly.
- Small head with seizures or 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's Head Growth Is Slow
Slow head growth (head circumference falling across percentile lines) warrants evaluation because it may indicate poor brain growth. However, some babies with small heads have familial microcephaly (small heads run in the family) and develop normally. Your pediatrician monitors head growth at every visit.
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.