Head circumference: measuring a child

The purpose of this guideline is to provide guidance about measuring a child's head circumference at Great Ormond Street Hospital (GOSH).


Assessment of growth is vital. It provides a sensitive guide to a child’s:

  • health 
  • development 
  • nutritional status 
  • response to treatment. 

The measurement of a child’s head circumference is part of this assessment.

Growth measurements encompass the measurement of height, weight and head circumference. The relationship of all these measurements will identify the need for further monitoring or investigation (ie a small head circumference with a low weight needs a different approach, compared to a small head with a normal weight).

An abnormal rate of growth could suggest a pathological disorder requiring diagnosis and possible treatment (eg hydrocephalus, psychosocial problems, craniosynostosis (Sniderman, 2010)).

The aim of measuring a head circumference is to determine the maximal head circumference.

It is performed to:

  • Monitor the growth of a child, particularly those under two years. However, it is still useful to continue to record a child’s head circumference, as it may detect any abnormalities that may develop after this period (Royal College of Paediatrics and Child Health (RCPCH), 2013)  (Rationale 1).
  • Detect abnormal brain or skull growth (eg hydrocephalus, craniosynostosis, microcephaly). 

All new born babies should have their head circumference measured. This should not be done before 36 hours of age. It should be done after 36 hours of age or preferably at 7–10 days (RCPCH, 2013) (Rationale 2).

Whenever an infant up to two years is admitted to GOSH, their head circumference must be measured. 

This measurement must be:

  • recorded in the child’s health care record 
  • recorded in the admission assessment record 
  • recorded in the child’s parent held record 
  • plotted on a centile chart.

The date, time and the name of the measurer must also be recorded. 

Any child who is admitted to GOSH with a known or suspected neurological or craniofacial abnormality, will need their head circumference recorded more frequently (eg an increase in the volume of cerebrospinal fluid (CSF) can result in an increasing head circumference (Rationale 3)). 

Unless specifically asked to do it more frequently, a child who attends the Outpatient department should normally have their head circumference measured at least every three months. 

For accuracy it is essential that a child’s head circumference is: 

  • measured using good equipment, for example, a Lasso-o™ measuring tape 
  • recorded with the date in the child’s health care records 
  • plotted correctly on a centile chart. 

A single measurement does not reflect the rate of growth (Rationale 4). 

The child must ideally be weighed at the same time as the head circumference is taken (Rationale 5). 

A Lasso-o™ is the recommended equipment to be used to obtain the measurement (Harris, 2013, Bartram et al., 2005) (Rationale 6)


Inform the family, and child if age appropriate, of the following (Rationales 7.8.9):

  • that a measurement of head circumference measurement is required 
  • the reason for the measurement 
  • what it entails 
  • the likely duration of the procedure. 

The child’s hairstyle must allow for accurate measurement (eg remove plaits or braids (Rationale 10)).

Hair adornments should be removed prior to measuring a child’s head circumference (Rationale 11).

The child’s health care records must indicate if any of these items are not removed (Rationale 12).

The child may require preparation from a play specialist or nurse, prior to measuring their head circumference (Rationale 13).

Measurement technique

The person measuring the child must first (Rationale 14):

  • apply standard precautions 
  • wear appropriate personal protective clothing to meet any identified risk 
  • perform a hand wash and thoroughly dry their hands. 


  • general clinical condition (eg irritability, vomiting (Rationale 15)) 
  • the fontanelle (ie open, closed, full, tense, soft, dipped (Rationale 15))
  • the shape of the child’s head (Rationale 15). 

To obtain the measurement:

  • Loop the Lasso-o™.
  • Place over the child’s head. 
  • The Lasso-o™ should be placed above the ears and midway between the eyebrows and the hairline to the occipital prominence at the back of the head (Bartram et al., 2005). However, this is a guide and as with any child, including children with an unusual shaped head, your aim is to always measure the largest circumference possible.
  • Pull the Lasso-o™ so that any hair is compressed. 
  • Read the measurement from the appropriately marked place on the Lasso-o™. 
  • The measurement should be taken to the nearest millimetre.  
  • Repeat the procedure above (Rationale 16). 
  • If a child has an abnormally shaped head (eg craniosynostosis, or a low hairline, eg Saethre-Chotzen syndrome), the Lasso-o™ should be placed over the largest measurable circumference (Rationale 17). This must be noted against the recorded measurement in the child’s health care records. 

Completing the procedure: general

Lasso-o™ is for single patient use only and will need to be discarded after use for that patient (Rationale 18).
Those involved in measuring the child’s head must perform a handwash following the procedure (Rationale 18).

Completing the procedure: documentation

The child’s head circumference must be (Rationale 19):

  • recorded in the child’s health care record 
  • recorded in the admission assessment record 
  • recorded in the child’s parent held record 
  • plotted on a centile chart of the correct gender. 

The date the measurement was made and the name of the person who made the measurement must also be included.

Please note: all three-year course pre-registration student nurses must have all measurements verified by a registered member of the nursing staff.

The “Four in One Growth Chart” is the centile chart that is recommended for general use (RCPCH, 2013) (Rationale 20).

A separate head circumference chart is available for children with achondroplasia and trisomy 21.

The head circumference should be plotted on the relevant grid of the growth chart with a well-defined dot and not a cross. The dot must not be circled. It should also be recorded in the recording box (RCPCH, 2013) (Rationale 21).

Measurements of growth need to be adjusted for prematurity if a child is born before 37 weeks gestation (RCPCH, 2013). 

The adjustment should continue to be made until the child is one year old, eg for a child who was born 20 weeks ago at 28 weeks gestation, draw a vertical line on the growth chart at 28 weeks and count 20 weeks across the grids. The measurement should therefore be plotted at eight weeks, which is the age adjusted for gestation (RCPCH, 2013).  

A child born at or after 37 weeks gestation does not need any adjustments to be made and measurements should be plotted from the expected date of delivery (RCPCH, 2013).

Completing the procedure: interpretation

The child’s doctor should be informed if (Rationale 22): 

  • The child’s head circumference measurement indicates excessive or limited growth. 
  • Their head is an abnormal shape or size (eg if the measurement falls outside 99.6th or 0.4th centile on the chart. 
  • The head circumference is >2 centile lines above or below their height or length measurement. 


Rationale 1: For those over two years it is less useful as the maximum head growth spurt is completed. 
Rationale 2: To allow for the effects of moulding and oedema from birth to settle. 
Rationale 3: To monitor the individual child’s condition. 
Rationale 4: Serial measurement allow for a more accurate assessment of a child's growth rate. 
Rationale 5: To enable interpretation of the measurement in the correct context. 
Rationale 6: They are easily made into flexible loops. 
Rationale 7: To obtain informed consent for the procedure. 
Rationale 8: To reduce anxiety. 
Rationale 9: To aid compliance. 
Rationale 10: To enable an accurate measurement to be obtained. 
Rationale 11: To avoid inconsistencies of measurements. 
Rationale 12: To maintain an accurate record. 
Rationale 13: To psychologically prepare the child and assist compliance. 
Rationale 14: To minimise the risk of cross infection.
Rationale 15: These symptoms could indicate a neurological deficit. 
Rationale 16: To ensure accuracy of measurement.
Rationale 17: To measure the head at the point where the circumference is greatest. 
Rationale 18: To minimise the risk of cross infection. 
Rationale 19: To maintain an accurate record. 
Rationale 20: So that the child's measurements can be compared to the average or normal measurements for children of the same gender and age, e.g. if a two-month-old is on the 75th percentile for weight, that means that 75 per cent of two-month-olds in the United Kingdom are lighter and that 25 per cent are heavier.
Rationale 21: To ensure original plotting is still visible. 
Rationale 22: These could indicate the need for further investigation. 


BARTRAM, J. L., RIGBY, A. S. & BAXTER, P. S. 2005. The "Lasso-o" tape: stretchability and observer variability in head circumference measurement. Arch Dis Child, 90, 820-1.

HARRIS, S. R. 2013. Congenital idiopathic microcephaly in an infant: congruence of head size with developmental motor delay. Dev Neurorehabil, 16, 129-32.

RCPCH. 2013. Early years - UK-WHO growth charts and resources. London: Royal College of Paediatrics and Child Health. [Last accessed 06.01.2017]

SNIDERMAN, A. 2010. Abnormal head growth. Pediatr Rev, 31, 382-4.

Document control information

Lead Author(s)

Lindy May, Nurse Consultant, Neurosciences

Additional Author(s)

Jacqueline Robinson-Rouse, Head of Nursing, Neurosciences
Zoe Wilks, Head of Nursing/Operational Manager, Outpatients
Jody O’Connor, Neurosurgical Nurse Practitioner

Document owner(s)

Lindy May, Nurse Consultant, Neurosciences

Approved by

Guideline Approval Group

Reviewing and Versioning

First introduced: 
12 November 2004
Date approved: 
03 January 2017
Review schedule: 
Three years
Next review: 
03 January 2020
Document version: 
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