Baby Head Circumference Measurement | Parenting Hub
Head circumference tracks brain growth. Learn how it's measured, what's normal, and when a sudden change matters.
Head circumference is a quick, painless way to track brain growth alongside weight and length.
Why it's measured
The head grows in step with the brain. Measuring around the widest part of the head — above the eyebrows and ears — gives a snapshot of brain growth. It's recorded at every MCH check in the first year.
What's normal
- Average newborn head is about 34–35 cm
- Grows around 2 cm per month for the first 3 months, then slows
- Should track along the baby's own curve
When to see a doctor
See your GP if the head measurement jumps across percentile lines suddenly, is well above or below the chart, or if the fontanelle is bulging.
When to seek help
- Sudden jump up across percentile lines
- Bulging fontanelle
- Head not growing at all over weeks