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.

Introduction

Assessment of growth is vital.  It provides a sensitive guide to a child’s (Ranjjana 2003; Ariza 2005):

• health

• development
• nutritional status
• response to treatment

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

A healthy, adequately nourished and emotionally secure child grows at an optimal rate (Stanhope 1994).

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 (Block 2005; May 2001).

Regular measurement of children in primary care can allow early diagnosis of these problems (Schlig, 1997).

An increasing head circumference may be the first or only indicator of a problem.

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 (Cox 1993). However, it is still useful/valuable to continue to record a child’s head circumference, as it may detect any abnormalities that may develop after this period. (Rationale 1)

• Detect abnormal brain/skull growth, eg hydrocephalus, craniosynostosis, microcephaly.

All newborn 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 (Lindley 1999; Sutter 1997) (Rationale 2).

Whenever an infant up to two years is admitted to Great Ormond Street Hospital (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 always 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 (Rationales 6 and 7). 

Cloth tape measures are not recommended (Batrum 2005; Fry 1994). 

The technique, including positioning of the Lasso-o™, used to obtain an accurate measurement of head circumference is crucial (Batrum 2005).

Preparation

Inform the family, and child if age appropriate, of the following (Rationales 8, 9 and 10):

• 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 11).

Hair adornments should be removed prior to measuring a child’s head circumference (Rationales 11 and 12).

The child’s health care records must indicate if any of these items are not removed (Rationale 13).

The child may require preparation from a play specialist or nurse, prior to measuring their head circumference (Rationale 14).

Measurement technique

The person measuring the child must first (Rationale 15):

• assess the need for universal precautions
• wear appropriate protective clothing to meet any identified risk
• perform a social hand wash and thoroughly dry their hands

The child may require play and distraction techniques to be utilised whilst obtaining the measurement (Rationale 16).

It is often easier if two people are involved in the measurement of a child (Rationales 17 and 18).

Ensure the child is made to feel safe and comfortable - this may involve sitting the child on another person’s lap (Rationales 9 and 10).

Assess:

• general clinical condition, eg irritability, vomiting (Rationale 19)
• the fontanelle, ie open, closed, full, tense, soft, dipped
• the shape of the child’s head (Rationale 20)

To obtain the measurement:

• Loop the Lasso-o™ (Rationale 21).
• 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 (Batrum and Baxter, 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 (Rationale 22).
• 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 21).
• 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 21). This must be noted against the recorded measurement in the child’s health care records.

Completing the procedure: general

The child should be left as comfortable as possible (Rationale 23).

Lasso-o™ is for single patient use only and will need to be discarded after use for that patient (Rationale 24).

Those involved in measuring the child’s head must perform a social handwash following the procedure (Rationale 24).

Completing the procedure: documentation

The child’s head circumference must be (Rationale 25):

• 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.

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

The “Four in One Growth Chart” is the centile chart that is recommended for general use (Fry 1994; Child Growth Foundation 1996) (Rationale 26).

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

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 (Fry 1994; Child Growth Foundation 1996) (Rationales 27 and 28).

The growth curve should be traced with a line that leaves the dots clearly visible (Rationale 29).

A normal growth curve is one that runs roughly on or parallel to one of the printed lines.

The measurement needs to be plotted in decimal. The decimal head circumference is obtained by: (Child Growth Foundation 1996) (Rationale 30)

• identifying the year of birth
• looking on the table to cross-reference the month of birth against the date of birth - this gives the decimal date of birth, eg 15 September 1998 is 98.704
• repeat the formula for the measurement date, eg 12 December 1999 is 99.945
• subtract one from the other and round off the last figure to give the decimal age, eg 1.24

Measurements of growth need to be adjusted for prematurity if a child is born before 37 weeks gestation. 

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. 

A child born at or after 40 weeks gestation does not need any adjustments to be made and measurements should be plotted from the expected date of delivery.

Completing the procedure: interpretation

The child’s doctor should be informed if (Rationale 31): 

• 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 >two centile lines above or below their height or length measurement.

Rationale

Rationale 1: For those over two years it is less useful because the “steep part” of the growing curve is over.
Rationale 2: To allow for the effects of moulding and oedema from birth to settle.
Rationale 3: To monitor their 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 do not stretch with use.
Rationale 7: They are easily made into flexible loops.
Rationale 8: To obtain 'informed consent'.
Rationale 9: To reduce anxiety.
Rationale 10: To aid compliance.
Rationale 11: To enable an accurate measurement to be obtained.
Rationale 12: To avoid inconsistencies of measurements.
Rationale 13: To maintain an accurate record.
Rationale 14: To psychologically prepare the child.
Rationale 15: To minimise the risk of cross infection.
Rationale 16: To minimise discomfort and distress.
Rationale 17: To help ensure an accurate measurement.
Rationale 18: To comfort the child.
Rationale 19: These could indicate a neurological problem.
Rationale 20: It could influence the positioning of the Lasso-o™.
Rationale 21: To ensure accuracy of measurement (Batrum JL and Baxter PS 2005).
Rationale 22: To measure the head at the point where the circumference is greatest (Batrum JL and Baxter PS 2005).
Rationale 23: To maintain safety and comfort of child.
Rationale 24: To minimise the risk of cross infection.
Rationale 25: To maintain an accurate record.
Rationale 26: It is based on the latest growth data.
Rationale 27: To maintain an accurate record.
Rationale 28: So that the child's measurements can be compared to the average or normal measurements for children of the same gender and age, eg 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 percent are heavier (Fry T 1994, Child Growth Foundation 1996).
Rationale 29: To ensure original plotting is still visible.
Rationale 30: The chart is divided into 10 not 12.
Rationale 31: These could indicate the need for further investigation.

References

Reference 1:
Ariza A, Greenberg R, LeBailly S (2005) Parent perspectives on messages to be delivered after nutritional assessment in pediatric primary care practice. Annals of the Family Medicine July: 3: 37-39.

Reference 2:
Batrum J L Baxter P S (2005) The Lasso-o tape: stretchability and observer reliability in head circumference measurement. Archives of Disease in Childhood 90 (8): 820 -821.

Reference 3:
Block R and Krebs F (2005) Failure to thrive as a manifestation of child neglect. Pediatrics 116 (5): 1234-1237.

Reference 4:
Child Growth Foundation (1996) Four-in-one growth charts. heightmatters.org.uk. Viewed on: 27/11/2006

Reference 5:
Child Growth Foundation (1996) Four-in-one growth charts. London, Child Growth Foundation

Reference 6:
Child Growth Foundation (Authors Schlig S Hulse T) (1997) Growth, monitoring and assessment in the community: A guid to good practice. www.heightmatters.org.uk. Viewed on: 27/11/2006

Reference 7:
Cox L A (1993) A guide to the measurement and assessment of growth in children. Ware, Castlemead Publications

Reference 8:
Fry T (1994) Introducing the new Child Growth Standards. Prof Care Mother Child 4 (8): 231.

Reference 9:
Lindley A A Benson J E Grimes C (1999) The relationship in neonates between clinically measured head circumference and brain volume estimated from head CT scans. Early Human Development 56(1): 17-29.

Reference 10:
May L (2001) Hydrocephalus May L. Paediatric Neorosurgery- a handbook for the multudisciplinary team. London, Whurr Publishers

Reference 11:
Ranjjana G Kirschner B (2003) Assessment of growth and Nutrition. Jornal of Pediatric Gastroenterology and Nutrition 17 (2): 153-16.

Reference 12:
Schlig S Hulse T (1997) Growth, monitoring and assessment in the community: A guide to good practice. London, Child Growth Foundation

Reference 13:
Stanhope R, Wilks Z, Hamill G (1994) Failure to grow: lack of food or lack of love?. Prof Care Mother Child 4 (8): 234-7.

Reference 14:
Sutter K, Engstrom JL, Johnson TS, Kavanaugh K, Ifft DL (1997) Reliability of head circumference measurements in preterm infants. Pediatr Nurs 23 (5): 485-90.

Document control information

Lead author(s)
Lindy May, Nurse Consultant, Neurosciences

Additional authors
Jacqueline Robinson-Rouse, Head of Nursing, Neurosciences
Zoe Wilks, Head of Nursing/Operational Manager, Outpatients

Document owner
Lindy May, Nurse Consultant, Neurosciences

Approved by
Clinical Practice Committee

First introduced: 12 November 2004
Date approved: 05 December 2011 
Review schedule: Two years
Next review: 05 December 2013
Document version: 3.0
Replaces version: 2.0