A Longitudinal Preterm Growth Reference

A study funded by the

MREC No: 07/ H0713/ 111

UCL Institute of Child Health

Co-ordinated by the Neonatal Data Analysis Unit

NDAUNeonatal Data Analysis Unit

The Study Team

Investigators

Professor Neena Modi, Professor Tim Cole, Dr Huiqi Pan

Research Fellow

TBA

NDAU Manager

Mr Richard Colquhoun

Objective

• To construct a growth reference for weight, length and

head circumference in preterm infants ≤ 34 weeks

gestation from birth to term/near term

• Using routinely collected clinical data entered into the

Standardised Electronic Neonatal Database (SEND)

and related neonatal.net systems

A growth chart is series of

smooth curves representing the

distribution of measurements of

interest within a population

Content of growth charts

a) Type of anthropometric indices

eg weight, length, head circumference

b) Summary data

eg z-scores and percentiles

c) Population

eg boys, girls

Cole TJ BMJ 1994;308:641-Cole TJ BMJ 1994;308:641-642642

Centiles and standard deviation score; Centiles and standard deviation score; the bulleted points are two thirds of an SDS apart.the bulleted points are two thirds of an SDS apart.

Is a neonatal chart a reference or a standard?

• A standard represents optimum growth

(prescriptive)

• A reference allows the comparison of any one

individual against a population (descriptive)

History of preterm growth charts

In 1948 Dancis et al published the first

Preterm Growth Reference Followed by:

1) Lubchenco et al (1963)

2) Battaglia et al (1966)

3) Usher and McLean (1969)

4) Babson et al (1970)

5) Brenner et al (1976)

Other Preterm Growth References

• Europe: Euro-Growth Reference; local (Brant 1976;

Excler 1987; Lozano 1998; Bertino 2006)

• Latin America: Gabriela (Chile 1989); Anchieta (Brazil

2004)

• China: Fok 2003

Growth reference charts used in the United Kingdom

• Tanner-Whitehouse • Buckler-Tanner • Cambridge • Harvard • Gairdner Pearson • UK 1990 Reference

The UK 1990 Growth Reference

Based on cross-sectional data, utilising

birth weights, and therefore not suitable

to follow longitudinal growth

Study Methods

POPULATION

Infants born ≤ 34 weeks gestation

admitted to neonatal units using a

neonatal.net electronic newborn record

• Maintain routine practice

• No extra procedures

• Measurements as clinical situation

permits

Standard Clinical Practice

Variables

Anonymised data comprising:

a) Gestational ageb) Sexc) Ethnicityd) Daily parenteral and enteral intakee) Maternal detailsf) Daily level of careg) Weight, length and head circumference

measurements from birth to discharge

Statistical AnalysisThe Cole LMS method will be used to construct

smooth curves summarising the distribution of

measurements by age and sex:

L = Skewness of distribution

M= Median of measurement

S= Coefficient of variation

Regulations and approvals

• Research Ethics approval obtained

• No patient consent required

• Site specific approval (SSA) exempt

• NHS Trust R&D approval necessary

• National Information Governance Board (NIGB) approval not needed as data are anonymised

What is required from participating units?

• Nomination of 2 local co-ordinators

• Liaison with the Neonatal Data Analysis Unit (NDAU)

• Entry of high quality anthropometric measurements, at

a frequency determined locally

• We recommend no greater than weekly intervals

The NDAU office will

• approach your R&D Office on your behalf to obtain Trust approval

• Local Principal Investigator not required

Anthropometric measurements

• Measurements taken by staff who have received training

• Recommend 3 repeat measurements if clinical situation

permits

• Head circumference measurement between the forehead

and the occiput with the hat removed

• Weight measured net of attachments/devices

• Length taken on a firm and flat surface by 2 people; 1

person holding the head whilst the other extends and hold

the feet against the foot rest

The neonatal.net record

Weight , head circumference and length measurements can be entered on any given day

1) Select Patient Name2) Go to Patient Home Page3) Select Patient Data4) Select Daily Data (left hand column)5) Go to Input Forms box6) Click on Daily Details to load the Summary Data 7) Enter the new data (weight, head circumference & length) at

the top of the Summary8) When complete, click Save and Close

Where are we now with the study?

To-date 77 UK neonatal units have

agreed to participate

Benefits of Participation

• Contribution to a national study

• The Child Growth Foundation will provide each

unit with newly designed equipment

• We will offer you on-site training in obtaining high

quality anthropometric measurements

References• 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;73:17-24

• Cole TJ, Green PJ. Smoothing reference centile curves: the LMS

method and penalized liklihood. Stat Med 1992; 11:1305-19

• Growth reference charts for use in the United Kingdom. Wright

CM, Booth IW, Buckler JM, Cameron N, Cole TJ, Healy MJ, Hulse

JA, Preece MA, Reilly JJ, Williams AF. Arch Dis Child 2002;86:11-

14

The new longitudinal reference will provide

a unique tool for child health professionals

to assess the growth of UK preterm infants

Overview

The Research Office

For further information or queries please contact:

Mr Richard Colquhoun

NDAU ManagerAcademic Neonatal MedicineImperial College LondonChelsea and Westminster Hospital 4th Floor, Lift Bank D369 Fulham RoadLondon, SW10 9NH 

T: 020 8746 5841

r.colquhoun@imperial.ac.uk