Girls Head chart in cms for babies 6 week old baby

Head circumference chart for 6-Week-Old girls

Head circumference milestones for baby girls at 6-Week-Old.

Head circumference percentiles for 6-Week-Old girls

Based on CDC and WHO reference data, head circumference percentiles for baby girls at 6-Week-Old are:

• 5th percentile: 35.8 cm

• 25th percentile: 37.0 cm

• 50th percentile (median): 38.0 cm

• 75th percentile: 39.0 cm

• 95th percentile: 40.6 cm

The percentile values on this page are displayed in cm.

A percentile shows how your child's measurement compares with baby girls of the same age and sex. Being at the 50th percentile means exactly half of baby girls measure more and half measure less.

Understanding growth at 6-Week-Old

At six weeks, head circumference has grown significantly since birth. This growth is driven by rapid increases in brain volume, myelination of nerve fibres, and the formation of cortical folds.

How to measure accurately

Head circumference is measured at the widest point - just above the eyebrows at the front and around the most prominent part at the back of the skull. Use a flexible, non-stretch tape measure. Two people make the task easier: one to hold the baby's head still, one to take the reading. Healthcare professionals use a purpose-built infantometer for length; for head, a standard tape is the clinical norm.

What to watch for

The fontanelle - the soft spot at the top of the head - should feel soft and slightly sunken when the baby is calm and upright. A bulging fontanelle when the baby is not crying may warrant prompt medical attention. A persistently sunken fontanelle can indicate dehydration. Keep a record of every head measurement with the date, as trends are far more informative than a single reading.

When to seek advice

Alert your GP or health visitor if the head circumference crosses two percentile lines upward or downward over a period of weeks, if the fontanelle closes very early (before 9 months) or remains widely open after 18 months, or if you notice unusual head shape that is not resolving on its own.

Frequently asked questions

What is the fontanelle and when does it close?

The fontanelle is the soft spot on the top of a baby's head where the skull bones have not yet fused. There are two fontanelles: the larger anterior (front) fontanelle, which typically closes between 9 and 18 months, and the smaller posterior (back) fontanelle, which usually closes by 2-3 months. Both allow the skull to expand rapidly as the brain grows during the first years of life.

What is a normal head circumference for this age?

The percentile table on this page shows the full range of typical head circumferences. All values from the 5th to the 95th percentile are within normal limits. As with all growth measurements, the pattern of growth over time is more informative than any single reading - a baby growing consistently at the 15th percentile is growing normally.

How fast does head circumference grow in the first year?

Head circumference grows approximately 10-12 cm in the first year of life - roughly 2 cm per month in the first 3 months, slowing to about 1 cm per month from 3-6 months, and 0.5 cm per month from 6-12 months. By 12 months, the average head circumference has grown from approximately 34-35 cm at birth to around 46-47 cm.

Data sources and methodology

The percentile ranges on this page are drawn from CDC growth chart data from the National Center for Health Statistics and WHO Child Growth Standards (for children under 5). CDC data published May 30, 2000, with 2022 extended BMI tables. Percentiles are modelled using the LMS method (Box-Cox transformation), which accounts for the skewed distribution of measurements at each age. All measurements are given in metric units with imperial equivalents.

For personalised guidance, consult a paediatrician or healthcare provider who can assess your child's measurements in the context of their full growth history.