Using the new UK-WHO growth charts

Using the new UK-WHO growth charts

SOCIAL PAEDIATRICS Using the new UK-WHO growth charts charts and their recommended use for different ages and settings are shown in Table 1. Early ...

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SOCIAL PAEDIATRICS

Using the new UK-WHO growth charts

charts and their recommended use for different ages and settings are shown in Table 1.

Early years charts UK-WHO birth to 4 years These new growth charts for children aged from birth to 4 years were introduced throughout the UK in May 2009 and are now including in the Personal Child Health Record (Red Book) for growth monitoring purposes to replace the existing UK90 nine centile growth charts which had been constructed from a variety of growth surveys conducted in the 1990s. They now use the World Health Organisation standard for child growth from age 2 weeks to 4 years and are thus referred to as the UK-WHO charts. These charts are unique in that they indicate how children should grow rather than being a description of how children actually grow (as with the UK90 charts). The WHO charts were based on growth data from many thousands of healthy breastfed children from around the world. All were born to non-smoking mothers after uncomplicated pregnancies and showed no subsequent health or environmental constraints to growth. The charts therefore provide a growth standard. Interestingly these children living in six very different countries around the world had very similar patterns of linear growth and so the charts can be used for all ethnic groups. The WHO standard does not include preterm data so the UK-WHO charts use re-analysed UK90 preterm and term birth weight data. UK children match the charts well for length and height at all ages, but the WHO growth chart places the weight centile lines lower down the page by a whole centile space during the second 6 months of life compared to the position of the UK90

Robert Moy Charlotte Wright On behalf of the Royal College of Paediatrics and Child Health Growth Chart Working Group

Abstract The Royal College of Paediatrics and Child Health has now published a complete set of growth charts for preterm infants up to adolescents for the purpose of surveillance and the assessment of individual children with health and growth problems. This paper describes the various new charts and advises on how they should be used. Novel features of the charts include look-up charts for Body Mass Index (BMI) centile, predicted adult height and mid parental centile. The charts now include detailed evidence based instructions on topics such as how to plot the growth of preterm infants and a simplified classification of the phases of puberty.

Keywords Down Syndrome; growth charts; growth monitoring; preterm; puberty

Introduction The Royal College of Paediatrics and Child Health (RCPCH) was commissioned by the Department of Health in 2008 to design new growth charts and develop new evidence based instructions for their use with supporting educational materials following a recommendation made by the Scientific Advisory Committee on Nutrition (SACN) that the new World Health Organisation (WHO) growth standard for children under 5 years should be introduced into general use in the UK. A multidisciplinary committee under the chairmanship of Professor Charlotte Wright was formed that included paediatricians, a statistician, an endocrinologist, neonatologist and representation from health visiting and school nursing and a growth chart design and publishing company. The committee first developed new growth charts for young children based on the WHO growth standard, but has since gone on to produce new charts for school aged children as well as charts aimed at children with health problems. There is now a complete set of charts for every use with all children from preterm infants up to adolescents. This paper describes the various charts and their novel features and advises on how they should be used. The different

Which chart for which child?

Robert Moy MD FRCPCH is Senior Lecturer in Child Health (Retired) at the College of Medical and Dental Sciences, University of Birmingham, UK. Conflicts of interest: none declared.

Age range

Community

Personal Child Health Record

32 weeks gestation to 18 years

Routine surveillance

UKeWHO Birth to 4 years

32 weeks gestation to 4 years

Detailed assessment

Routine use

Neonatal and Infant Close Monitoring

23 weeks gestation to 2 years corrected

Very preterm and weight faltering

Sick and preterm infants

School age 2e18 years

2e18 years (usually from 4)

Individual assessment

Routine use

Childhood and Puberty Close Monitoring

2e20 years

Special schools, obesity services

Children at extremes of growth

All children with Down Syndrome

All children with Down Syndrome

Down Syndrome 0e18 years

Charlotte Wright MD FRCPCH is Professor of Community Child Health at the University of Glasgow, PEACH Unit, QMH Tower, Yorkhill Hospital, Glasgow, UK. Conflicts of interest: none declared.

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Secondary care

Table 1

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Figure 1 Detail from girl’s chart showing separate preterm section, age zero for plotting all births from 37 weeks gestation, birth centiles, no centiles between 0 and 2 weeks and labelling of 50th centile.

Figure 2 Left panel: gestational age correction by arrow drawn backwards the number of weeks preterm (7 weeks). Right panel: incorrect plotting of same measurements without gestational age correction misleadingly showing apparent weight faltering. PAEDIATRICS AND CHILD HEALTH 24:3

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ft/in • Plot the most recent height

6.5

• Find corresponding centile on the adult scale

6.4

• Four out of five children will be within 6 cm of this values as adults For example, if a child is on the 75th centile for height, the adult predictor suggests he or she may reach an adult height of 181 (range 175–187) cm.

to 36 weeks of gestation. All birth weights from 37 completed weeks of gestation are plotted at age zero on the infancy chart. Birth measurement centiles for term infants are then read from tabs on the weight axis. This is because there are no centile lines during the first 2 weeks of age during which young infants may normally lose weight and then regain birth weight. During this period, it is more important to assess percentage weight loss compared to the birth weight rather than actual centile position (Figure 1). The chart now carefully describes both the definition of prematurity and how measurements for preterm infants should be plotted as this is an aspect that is often poorly understood (see Figure 2) Children born between 32 and 36 completed weeks’ gestation are plotted on the preterm section of the chart until 2 weeks post-term (Figure 1). After that their measurements are plotted on the infancy chart with a gestation age correction using the “arrow drawn back” method (Figure 2) thereby reducing the risk of plotting errors. Gestational age correction is continued up to the age of 12 months for infants born after 32 weeks gestation. However infants born more than 8 weeks preterm should be plotted on the chart below. The layout of the chart no longer emphasizes the 50th centile, as the bold line on previous charts was found to mislead parents to expect normal infants would grow along this line. The charts also features a new adult height predictor tool (Figure 3) and the A4 version of the chart also includes a look up that provides the child’s Body Mass Index centile (and thereby obesity status) from weight and height centiles without the need for calculation (Figure 4).

cm 195

99.6th 6.3

6.2

6.1

190 98th

91st

185

6.0 75th 5.11

5.10

180 50th

5.9

175 25th

5.8

5.7

5.6

9th

170

2nd

Figure 3 Adult height predictor tool for boys.

Neonatal and Infant Close Monitoring (NICM) chart This chart has been designed for plotting the growth measurements of preterm and low birth weight infants from 23 weeks gestation to the corrected age of two years, but is also suitable for term neonates or young infants requiring close monitoring because of health problems or weight faltering. It is based on reanalysed UK90 data and illustrates the size at birth of UK infants born at 23e42 weeks gestation around 1990. The chart does not describe how preterm infants grow after birth because it shows only birth measurements of infants born at different

centiles. This means that there will now be fewer infants with low weight but more children at the higher centile end of the weight chart. By school age the difference between the UKWHO and UK90 weight charts become much smaller. Length and height are very similar at all ages. The head circumference chart however shows significant differences between the UK-WHO and UK90 charts with UK children tending to have larger heads and to cross centile spaces upwards. Consequently with the use of the UK-WHO head circumference chart, it will be more common to observe head circumferences above the 98th centile and upward centile crossing which should not raise concern unless there is associated abnormal developmental progress or other signs of raised intracranial pressure, and it will be unusual to find infants with head circumferences below the 2nd centile and infants displaying downward crossing of more than two centile spaces. The UK-WHO charts introduce a number of new features. There is a separate preterm birth section for infants born from 32

Figure 4 Body Mass Index look up tool for ascertaining BMI centile.

165

5.5 0.4th 5.4

5.3

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Figure 5 Neonatal and Infant Close Monitoring chart date boxes.

gestational ages. It has a large scale to allow detailed monitoring and low reading (SD) lines to allow assessment of very small infants. Gestational age correction is not required on this chart as the time axis runs continuously from the preterm birth to the age of 2 years. The chart needs calibrating by completion of the date boxes prior to use using the attached calendar (Figure 5).

Children being plotted on this chart can be transferred at age 2 to the school age charts described below.

School age charts 2e18 years chart This chart is intended for the assessment of growth in school age children and will most commonly be used from the age of four year onwards for the assessment of individual children rather than for population growth monitoring purposes. It combines data from the UK90 growth reference for children at birth and from 4 to 18 years with the WHO growth standard for children aged 2e4 years. It includes a number of new features which can be used, when relevant, to help in the interpretation of growth and development. The chart only starts at age 2 years, so there is a plotting scale on the left of the chart where birth weight (and length, if measured) for children born at term (after 37 completed weeks) can be plotted, to allow comparison of the birth centile with later growth. Like the 0e4 chart there is a BMI centile look up and an adult height predictor but in addition this chart has a scale that converts parental height into a ‘mid-parental centile’ (Figure 6). This is simpler and more statistically valid than the traditional target height calculation, since very tall and short parents tend to have children with less extreme heights and this scale allows for this. Comparing this to the child’s current height centile can help assess whether this child’s growth is proceeding as expected. Nine out of ten children’s height centiles are within two centile spaces above or below the mid-parental centile and only 1% will be more than three centile spaces below. If there are other concerns about the child’s growth rate, a height centile well below the mid-parental centile should be investigated further. However comparison with parents’ height is not a pass/fail test for normal height and a child growing abnormally may still be within mid parental height range. The right hand page of the school age charts shows the period during which normal puberty should begin and progress. The new

Figure 6 Parent height comparator.

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Figure 7 Pubertal phase assessment chart.

Puberty phases by history from parents, carers, or young person Pre-puberty (Tanner stage 1) If all of the following

In puberty (Tanner stage 2e3) If any of the following

Completing puberty (Tanner stage 4e5) If all of the following

Girls

No signs of pubertal development

Any breast enlargement pubic or axillary hair,

Boys

High voice and no signs of pubertal development

Slight deepening of the voice Early pubic or axillary hair growth Enlargement of testes or penis

Started periods with signs of pubertal development Voice fully broken Facial hair Adult size of penis with pubic and axillary hair

Table 2

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charts use simplified classification of puberty which usually avoids the need for intimate examination, using just three phases. “Pre-puberty”, “In Puberty” and “Completing Puberty”. Children with measurements plotted on the left hand page of the chart will usually be in the ‘Pre puberty’ phase. Signs of puberty before 8 years in girls and 9 years in boys are precocious and further assessment is necessary. Three vertical black lines (puberty lines) indicate the normal age limits for the phases of puberty described above (Figure 7). These charts also provide some extra guidance about the lower limit (0.4th) for height in girls 8e13 years and boys 9e14 years who are still in pre puberty.

Where to obtain the charts, equipment and further information The UK-WHO and School Age charts can be purchased from Harlow Printing, Maxwell Street, South Shields NE33 4PU or from sales@ harlowprinting.co.uk. Appropriate measurement equipment can be purchased from www.healthforallchildren.co.uk. Educational materials including Fact sheets, Activity Sheets and PowerPoint presentations are freely available for download at www.growthcharts.rcpch.ac.uk.

Childhood and Puberty Close Monitoring chart This is a modification of the main school age chart for use in children with growth or nutritional problems and will be ideal for use in specialist clinics and special schools. The chart extends to age 20 years and features: additional high and low SD lines to monitor unusually short, thin or overweight children and a full BMI chart. It also includes additional guidance on pubertal assessment using both the three phases of puberty as listed above and Tanner puberty stage-by-age charts (Table 2).

FURTHER READING Cole TJ, Wright CM, Williams AF. Designing the new UK-WHO growth charts to enhance assessment of growth around birth. Arch Dis Child Fetal Neonatal Ed 2012; 97: F219e22. Cole TJ, Wright CM. A chart to predict adult height from a child’s current height. Ann Hum Biol 2011; 38: 662e8. Cole TJ. A chart to link child centiles of body mass index, weight and height. Eur J Clin Nutr 2002; 56: 1194e9. Freeman JV, Cole TJ, Chinn S, Jones PRM, White EM, Preece MA. Cross sectional stature and weight reference curves for the UK, 1990. Arch Dis Child 1995; 73: 17e24. Scientific Advisory Committee on Nutrition (SACN). Application of WHO growth standards in the UK. London: Stationery Office, 2008. Styles ME, Cole TJ, Dennis J, Preece MA. New cross sectional stature, weight and head circumference references for Down’s syndrome in the UK and Republic of Ireland. Arch Dis Child 2002; 87: 104e8. World Health Organisation. The WHO child growth standards, 2006. www. who.int/childgrowth/en/. Wright CM, Williams AF, Elliman D, et al. Using the new UK-WHO growth charts. BMJ 2010; 340: 647e50. Wright C, Cheetham T. The strengths and limitations of parental heights as a predictor of attained height. Arch Dis Child 1999; 81: 257e60. Wright C, Lakshaman R, Emmett P, Ong KK. Implications of adopting the WHO 2006 Child Growth Standard in the UK: two prospective cohort studies. Arch Dis Child 2008; 93: 566e9. Wright CM, Inskip HM, Godfrey K, Williams AF, Ong KK. Monitoring head size and growth using the new UK-WHO growth standard. Arch Dis Child 2011; 96: 386e8. Wright CM, Williams AF, Cole TJ. Advances in growth chart design and use: the UK experience. World Rev Nutr Diet 2013; 106: 66e74.

Down Syndrome chart This chart is based on data from around 6000 growth measurements of 1100 healthy children with Down Syndrome who were growing up in the UK and Ireland between 1980 and 2000 and is suitable for all children with Down Syndrome, from term. It uses a large scale in the early months and includes low lines to aid assessment of children with additional health problems. Preterm children with Down Syndrome should be plotted on the NICM chart the until age of 2 weeks. A

Measurement C

C C

C C

C

Anyone who measures children should be properly trained and have the correct equipment. Babies should be weighed without any clothes or nappy. Children older than two years can be weighed in vest and pants and without shoes. Weighing scales must be class III electronic scales. Proper equipment is also required for measuring length and height. Head circumference should be measured using a narrow plastic or paper tape around the widest head circumference.

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