- Email: [email protected]
Growth charts in neonates
CMRP-172; No. of Pages 6 current medicine research and practice xxx (2016) xxx–xxx
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/cmrp
Review Article
Growth charts in neonates Sujit Shrestha, Anup Thakur, Sanket Goyal, Pankaj Garg, Neelam Kler * Department of Neonatology, Sir Ganga Ram Hospital, New Delhi, India
article info
abstract
Article history:
There has been a continuous effort to develop standard growth charts for neonates.
Received 16 January 2016
Reference growth charts based on cross-sectional intrauterine data were developed from
Accepted 17 March 2016
measurement of anthropometric parameters of neonates of different gestations at birth.
Available online xxx
Similarly postnatal charts for preterm neonates were developed based on longitudinal measurements of infant's parameters over intervals. Fetal–infant growth charts were
Keywords:
devised by combining cross-sectional intrauterine data and postnatal infant's longitu-
Growth charts
dinal parameters. Revised Fenton 2013 charts incorporating neonatal anthropometric
Neonatal
data look to be most adequate for preterm infants of 22 weeks gestation till 50 weeks
Fetal
post-menstrual age. These growth references describe how infants grew in certain time
Head circumference
in a defined population. There was a need of developing growth standard defining growth of healthy population in optimal conditions. WHO Multicentre Growth Reference Study charts were developed as growth standards describing the growth of healthy children from term gestation till 5 years of age. Intergrowth 21st growth chart is the new growth standards for preterm infants and looks promising in infants of gestation 33 weeks or more. # 2016 Sir Ganga Ram Hospital. Published by Elsevier, a division of Reed Elsevier India, Pvt. Ltd. All rights reserved.
1.
Introduction
Growth is described as a net increase in size or mass of tissues as a result of either multiplication of cells or increase in intracellular substance.1 Fetal growth is the most rapid phase of growth in humans and exponential growth occurs by six folds between 22 and 40 weeks.2 It is influenced by fetal, placental and maternal factors. Under normal environment, a fetus grows as per its inherent growth potential to an appropriate size newborn. After birth, baby's growth is
determined by genetic potential and various internal and external factors.1 Infants are in a continuous process of growth. It is important to monitor the growth of infants to detect any deviation from normal. During hospital stay, a rapid change in weight may occur due to fluid overload or due to catch-up growth. Low gain may be due to inadequate nutrition or concurrent illnesses. Growth faltering in neonatal period can be due to faulty feeding, infections, cold stress, anemia and metabolic disturbances.3,4 Growth monitoring also helps in identifying babies at high risk of having poor neurodevelopmental outcome. Higher linear
* Corresponding author. Tel.: +91 9811047391; fax: +91 1125861002. E-mail address: [email protected] (N. Kler). http://dx.doi.org/10.1016/j.cmrp.2016.03.009 2352-0817/# 2016 Sir Ganga Ram Hospital. Published by Elsevier, a division of Reed Elsevier India, Pvt. Ltd. All rights reserved.
Please cite this article in press as: Shrestha S, et al. Growth charts in neonates, Curr Med Res Pract. (2016), http://dx.doi.org/10.1016/j. cmrp.2016.03.009
CMRP-172; No. of Pages 6
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current medicine research and practice xxx (2016) xxx–xxx
growth,5 weight gain and head growth are associated with better neurodevelopmental outcome including decreased incidence of cerebral palsy especially in extremely low birth weight babies.6 An important tool for growth monitoring in neonates is growth charts. Two common types of growth charts are 'growth references' and 'growth standards'. A 'growth reference' is a statistical summary of anthropometry in a reference group of children, whose health status is not taken into consideration.7 These charts are descriptive and show how children grow rather than how they should grow.8 A 'growth standard' is essentially the same as a growth reference except that the underlying reference sample is selected on health grounds. It is a prescriptive model representing a healthy pattern of growth and shows how the child should grow. Standard charts have the ability to diagnose overweight and obesity early and also avoid over diagnosis of undernutrition.7,8
2.
Neonatal growth charts
Historically, the idea of plotting a child's anthropometric parameters on a chart to illustrate the pattern of growth was first conceived by Count Philibert de Montbeillard of France in the 18th century. He plotted his son's height every six month from birth till the age of 18 years. Henry Bowditch was the first to use the centiles to describe the growth of Massachusetts children in 1891.7 Lubchenco's chart was amongst the first intrauterine growth chart to be widely used in neonates. It also classified newborns based on size at birth.9 Over last five decades, number of standard and reference charts have been developed for monitoring growth of term and preterm neonates.
2.1.
Reference growth charts
Reference growth charts used in preterm infants are: A. Intrauterine growth charts: Intrauterine growth charts are those that are derived from data of anthropometric measurements of preterm infants of different gestational age at birth. Available intrauterine charts are Lubchenco (1966), Usher and McLean (1969), Brenner (1976), Arbuckle (1993), Alexander (1996) and Kramer (2001).10 The drawbacks of these intrauterine charts are that they are based on small sample size and are not gender specific. Most of these charts used last menstrual period (LMP) to estimate gestation age instead of first trimester ultrasound (USG), which is less reliable.11 These charts are cross-sectional and lack the ability to describe longitudinal fetal growth.12 There are serious concerns about using them as standards, as preterm infants are different from fetus.10 Lubchenco charts (1948–1961) based on population of around 4700 newborns having gestation age from 26 to 42 weeks was one of the most widely used intrauterine growth charts. It was based on a multi-centric retrospective study, which included both term and preterm infants. Weight, length and head circumference were retrieved and smooth
growth curves were developed. Battaglia and Lubchecho were the first to describe newborns as small for gestation age, appropriate for gestation age and large for gestation age.9,13 The drawbacks of these charts are that they are based on population of only one country (USA) and included population of high altitude which are more likely to be growth restricted.14,15 B. Postnatal growth charts: These growth charts are based on longitudinal measurements of parameters of infants as they grow and as such provide actual postnatal pattern of infant's growth. Growth chart developed from these data as such cannot be prescriptive, as defining a healthy preterm is not possible.10 Postnatal growth charts include Dancis 1948, Infant Health and Development Program (IHDP) 1985, Shaffer 1987, Wright 1993, Berry 1997, Ehrenkranz 1999. These charts demonstrated the weight loss pattern after birth, regain of birth weight and subsequent growth.16,17 One of the popularly used postnatal charts was charts by Ehrenkranz (1999). It was based on a multicentric prospective cohort study from 12 centers based in USA and included 1660 infants with birth weights between 501 and 1500 g admitted within 24 h of age. Longitudinal data on weight, length, head circumference and mid-arm circumference were measured from birth until discharge, transfer, death, age 120 days, or a body weight of 2000 g. The strength of these charts is that they consist of a large, heterogeneous population of very low birth weight infants and included infants, who received more advance treatments such as surfactant replacement therapy, antenatal steroid and early aggressive nutritional regimens. These growth curves may be used to understand postnatal growth better and to identify infants developing morbidities affecting growth such as bronchopulmonary dysplasia. Drawbacks are that it is based on a small sample size and derived from population of a single country.18 Another significant shortcoming of use of this chart in practice is that it only provides a single line trajectory and not major centiles. C. Fetal–infant growth charts: These charts are constructed by merging two sets of reference data: cross-sectional data of anthropometric measurement of preterm infants at birth and postnatal longitudinal anthropometric data of term infants. Therefore, these charts permit growth comparison with fetus first and then to term standards. The advantage of using fetal–infant growth chart is that it allows to assess if a preterm neonate is achieving catch up growth or not.17 Examples are – Babson and Benda charts 1967, Fenton chart 2003 and Fenton charts 2013.2,19,20 Babson and Benda obtained anthropometric data of infants of mostly Caucasian population, with gestation age 27 to 44 weeks born between 1959 and 1966. It was popularly used but had limitations of not including neonates of lower gestation and had 500 g weight interval increments. This made precise plotting difficult.19 Fenton in 2003, updated the Babson–Benda charts and created new chart that could be used from gestation 22 weeks to 50 weeks. It allowed comparison of growth of a preterm infant with that of fetus initially starting as low as 22 weeks till 36 weeks and then later with term infants upto
Please cite this article in press as: Shrestha S, et al. Growth charts in neonates, Curr Med Res Pract. (2016), http://dx.doi.org/10.1016/j. cmrp.2016.03.009
CMRP-172; No. of Pages 6
3
current medicine research and practice xxx (2016) xxx–xxx
Table 1 – Data sources used by Fenton in 2013 charts. Data source
Voight 2010
Olsen 2010
German perinatal survey
Pediatrix Medical Group hospital
Sample size N < 30 weeks Dates Data
23,000,000 14,146 1995–2000 Weight
Gestational assessment
USG 8–14 weeks and Naegle's rule
130,111 11,377 1998–2006 Weight, head and length Clinical assessment
Kramer 2001
Robert 1999
Canadian Australian national file national perinatal statistical unit
Bonellie 2008
Bertino 2010
Scottish maternity data collection
Italian neonatal study
676,605 3247 1994–1996 Weight
734,145 3193 1991–1994 Weight
100,133 2053 1998–2003 Weight
Early USG
Dates, prenatal or postnatal assessment
Clinical assessment based on USG, LMP
45,462 623 2005–2007 Weight, head, length USG 1st trimester
Table derived from Fenton and Kim.2
50 weeks. Data from studies including large population of newborns were used. Curves based on large preterm population were obtained but these charts were not sex specific and were designed for plotting as completed gestation weeks. Moreover the methodological quality and heterogeneity affected its validity.20 In 2013, revised Fenton charts were published. These charts were based on large preterm birth sample size of approximately 4 million infants. Data between 1991 and 2007 from developed countries (Germany, Italy, United States, Australia, Scotland and Canada) were included (as shown in Table 1). Advantages of these charts are that they include data from recent population based surveys and are sex specific. It can also be used to assign size for gestational age up to 36 weeks. Besides these, the curves are equivalent to the WHO growth curves at 50 weeks of post-menstrual age (PMA) (10 weeks post-term age) and therefore after this age WHO curves can be used. The chart is also advantageous as it enables to plot growth parameters of infants in between weeks and not as completed weeks. Apart from the studies mentioned in Table 1, data of 882 term babies were obtained from WHO Multicentre Growth Reference Study (MGRS)21 to smoothen the curves. The drawbacks are that Fenton 2013 is a growth reference and not a growth standard.2 Data plotted in 2013 Fenton Chart should be interpreted with caution in two aspects. First, similar to Fenton 2003, it does not address the physiological postnatal loss of body water after birth. Further, different centers used variable methods for measurement of crown-heel length, making its reliability doubtful. Another criticism is that Fenton used data of term babies to smoothen some portion of the chart used for preterm babies.22 However, this portion of curves between 37 and 50 weeks was later validated in another study where data disjuncture occurred by comparing them using weight gain patterns of contemporary preterm infants.23 Fenton growth curves 2013 for girls (Fig. 1) and boys from 22 to 50 weeks are available from http://www.ucalgary.ca/fenton/ 2013chart. Peditools.org is an online clinical tool available for easier calculation of centiles and z score as described by Fenton (Fig. 2).24 (Available at http://peditools.org/fenton2013.)
2.2.
Standard growth charts
The WHO growth standard 2006 for children are based on data from the WHO MGRS, conducted during 1997–2003 in six different countries of different continents including India. Data were based on both developed and developing nations. As per standard recommendation, the population sample included only full term breast fed infants whose growth was not restrained by socioeconomic status. Population of high altitude (>1550 m), infants born to mothers who smoked and those with perinatal complications were excluded. The growth curves for children aged below 24 months were based on the
Fig. 1 – Fenton fetal infant growth chart 2013, chart for girls.
Please cite this article in press as: Shrestha S, et al. Growth charts in neonates, Curr Med Res Pract. (2016), http://dx.doi.org/10.1016/j. cmrp.2016.03.009
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current medicine research and practice xxx (2016) xxx–xxx
Fig. 2 – Software for calculation of z score and centile of Fenton chart 2013.
longitudinal component of MGRS. In the first 2 months data were collected at birth, 1 week, and every 2 weeks, then monthly till 12 months age and bimonthly from 14 to 24 months. On the contrary, the curves for children from 24 to 59 months were based on the cross-sectional component of MGRS. However the data in both the components were collected in the same community. To eliminate the effect of overweight, infants whose weight measurements were more than 2 standard deviations above the study median were excluded from the analysis.21 Unlike previous charts, WHO charts are growth standards, prescriptive in nature and also delineates children with obesity. These standards have been used by 125 countries. The main drawback is that, the WHO charts do not address babies of preterm gestation. WHO charts have been used in premature neonates after they reach 40 weeks PMA.2 The Intergrowth-21st Project was initiated by International Fetal and Newborn Consortium with the aim to produce new prescriptive standards describing normal fetal and newborn growth. Data were collected from 8 geographically different areas. Countries included were China, India, Italy, Oman, Brazil, Kenya, UK and USA. The study objectives were to generate international growth standards based on fetal growth from early pregnancy: Fetal growth longitudinal study (FGLS), standards for postnatal growth of preterm: preterm postnatal follow-up study (PPFS) and to determine newborn size at birth: newborn cross-sectional study (NCSS). Both LMP and USG combined over a time by a two stage process were used as a measure to ascertain gestation age. FGLS included anthropometric data of fetus from 14 weeks gestational age to birth for monitoring fetal growth clinically and by USG in a healthy population. Standard fetal growth curves were constructed based on USG for occipito-frontal diameter, head circumference and abdominal circumference, in addition to biparietal diameter and femur length. It is devised to be used for the clinical interpretation of routinely taken USG measurements. Of 4607 pregnant women enrolled
in FGLS, 224 went on to have preterm delivery.25 For PPFS, all preterm newborns of more than 26 weeks and less than 37 weeks were followed post-delivery for evaluation of postnatal growth. A total of 201 eligible preterm newborns from FGLS who met criteria of healthy or stable preterm were included. Standards for postnatal growth in preterm infants were obtained for weight, length and head circumference that can be used for assessment up to 64 weeks PMA.26 In the NCSS, a total of 20,486 eligible women were enrolled between May 2009 and August 2013. Weight, length and head circumference of all newborn infants whose mothers were enrolled in FGLS and those born within the Intergrowth-21st geographical areas during a fixed period of 12 months (FGLS-like population) were measured within 12 h of birth. Centile curves for 3rd, 10th, 50th, 90th, and 97th were obtained according to gestational age and sex. Prescriptive international anthropometric standards to assess newborn size from 33 to 43 weeks gestation were obtained from this study.26,27 Characteristics of these new charts are that it bridges gaps in clinical and population assessments for fetuses, neonates and infants through provision of similar instruments to monitor child growth continuously from early prenatal life up to the age 5 years. The standards obtained are populationbased, multiethnic, multi-country and sex-specific and they arise from a prospective study. Across all the eight study sites, not only a uniform research method and same protocol was used but also accurate gestational age estimation was ensured by 1st trimester USG. The methodology was further strengthened by use of identical equipment, training, a centralized electronic data management system and close monitoring of staff. Therefore, the standards are prescriptive and describe the optimum size in newborn infants without congenital abnormalities. Software is also made available for clinical and epidemiological use to calculate z scores and centiles (http://intergrowth21.ndog.ox.ac.uk/en/ ManualEntry). Standard charts obtained from PPFS charts used to assess preterm babies up to 64 weeks PMA overlapped
Please cite this article in press as: Shrestha S, et al. Growth charts in neonates, Curr Med Res Pract. (2016), http://dx.doi.org/10.1016/j. cmrp.2016.03.009
CMRP-172; No. of Pages 6 current medicine research and practice xxx (2016) xxx–xxx
with WHO MGRS chart.26 Limitations were that despite a large sample size, there were relatively few early preterm births below 33 weeks for PPFS study. In NCSS the lower limit of the curves was set at 33 weeks of gestation, because it was not possible to enroll preterm below this gestation age with very strict criteria.26,27
6.
7.
3.
Conclusion
With the increase in preterm survival, the concern regarding the use of appropriate growth chart to assess preterm growth is increasing. Therefore, there is a continuous effort to develop a standard growth chart for preterm infants, which can be used with confidence across all gestations and population. Intrauterine growth charts such as Lubchenco chart cannot be used for longitudinal assessment of growth. Ehrenkranz charts were developed for longitudinal growth monitoring of preterm infants but the study had a small sample size and do not provide gestation specific centiles. Intergrowth-21st postnatal growth standard for preterm infants was devised to address this issue and create a preterm postnatal growth standard from a prospective cohort from different geographical areas making them the recommended charts for neonates with gestation week 33 or more.28 However, as it had less number of infants below 33 weeks (28 infants) they may still not be useful in infants of lower gestation. Though Fenton charts 2013 are reference charts for preterm infants and lack standard prescriptive benefits, they still seem to be popular for preterm infants because they include data from 4 million preterm infants, allows precise sex specific plotting and smooth transition to WHO MGRS 2006 growth standards charts and can be used for preterm babies from 22weeks till 50 weeks PMA. We emphasize that for term infants, WHO MGRS 2006 growth charts should be used.29 As WHO MGRS charts are being widely used and the Intergrowth-21st charts showed reproducible results, it is expected to be accepted worldwide as well. However, these charts are still in process of implementation.
8. 9.
10. 11.
12.
13.
14.
15.
16.
17. 18.
19.
Conflicts of interest
20.
The authors have none to declare.
21.
references 22. 1. Paul VK, Bagga A. Ghai Essential Pediatrics. 8th ed. CBS; 2013. 2. Fenton TR, Kim JH. A systematic review and meta-analysis to revise the Fenton growth chart for preterm infants. BMC Pediatr. 2013;13:59. 3. Marks KA, Reichman B, Lusky A, Zmora E. Israel Neonatal Network. Fetal growth and postnatal growth failure in verylow-birthweight infants. Acta Paediatr. 2006;95(2):236–242. 4. Clark RH, Thomas P, Peabody J. Extrauterine growth restriction remains a serious problem in prematurely born neonates. Pediatrics. 2003;111(5 Pt 1):986–990. 5. Ramel SE, Demerath EW, Gray HL, Younge N, Boys C, Georgieff MK. The relationship of poor linear growth velocity
23.
24. 25.
with neonatal illness and two-year neurodevelopment in preterm infants. Neonatology. 2012;102(1):19–24. Ehrenkranz RA, Dusick AM, Vohr BR, Wright LL, Wrage LA, Poole WK. Growth in the neonatal intensive care unit influences neurodevelopmental and growth outcomes of extremely low birth weight infants. Pediatrics. 2006;117(April (4)):1253–1261. Cole TJ. The development of growth references and growth charts. Ann Hum Biol. 2012;39(5):382–394. Patole BS. Nutrition for the Preterm Neonate: A Clinical Perspective. 1st ed. Netherlands: Springer; 2013. Lubchenco LO, Hansman C, Dressler M, Boyd E. Intrauterine growth as estimated from liveborn birth-weight data at 24 to 42 weeks of gestation. Pediatrics. 1963;32(November): 793–800. Preedy VR. In: Al-Wassia H, ed. In: Handbook of Growth and Growth Monitoring in Health and Disease. Springer; 2012. Dietz PM, England LJ, Callaghan WM, Pearl M, Wier ML, Kharrazi M. A comparison of LMP-based and ultrasoundbased estimates of gestational age using linked California livebirth and prenatal screening records. Paediatr Perinat Epidemiol. 2007;21(suppl 2):62–71. Kramer MS, Platt RW, Wen SW, et al. A new and improved population-based Canadian reference for birth weight for gestational age. Pediatrics. 2001;108(2):E35. Lubchenco LO, Hansman C, Boyd E. Intrauterine growth in length and head circumference as estimated from live births at gestational ages from 26 to 42 weeks. Pediatrics. 1966;37 (3):403–408. Moore LG. Fetal growth restriction and maternal oxygen transport during high altitude pregnancy. High Alt Med Biol. 2003;4(Summer (2)):141–156. Waldhoer T, Klebermass-Schrehof K. The impact of altitude on birth weight depends on further mother- and infantrelated factors: a population-based study in an altitude range up to 1600 m in Austria between 1984 and 2013. J Perinatol. 2015;35(9):689–694. Wright CM, Parkinson KN. Postnatal weight loss in term infants: what is normal and do growth charts allow for it? Arch Dis Child Fetal Neonatal Ed. 2004;89(3):F254–F257. Griffin IJ. In: Fenton TR, ed. In: Perinatal Growth and Nutrition. CRC Press; 2014. Ehrenkranz RA, Younes N, Lemons JA, et al. Longitudinal growth of hospitalized very low birth weight infants. Pediatrics. 1999;104(2 Pt 1):280–289. Babson SG, Benda GI. Growth graphs for the clinical assessment of infants of varying gestational age. J Pediatr. 1976;89(November (5)):814–820. Fenton TR. A new growth chart for preterm babies: Babson and Benda's chart updated with recent data and a new format. BMC Pediatr. 2003;3:13. de Onis M, Garza C, Onyango AW, Rolland-Cachera MF. le Comite de nutrition de la Societe francaise de p [WHO growth standards for infants and young children]. Arch Pediatr. 2009;16(1):47–53. Pereira-da-Silva L, Virella D. Is intrauterine growth appropriate to monitor postnatal growth of preterm neonates? BMC Pediatr. 2014;14:14. Fenton TR, Nasser R, Eliasziw M, Kim JH, Bilan D, Sauve R. Validating the weight gain of preterm infants between the reference growth curve of the fetus and the term infant. BMC Pediatr. 2013;13:92. Fenton T. University of Calgary. Available from: http://www. ucalgary.ca/fenton/2013chart. Papageorghiou AT, Ohuma EO, Altman DG, et al. International standards for fetal growth based on serial ultrasound measurements: the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project. Lancet. 2014;384 (9946):869–879.
Please cite this article in press as: Shrestha S, et al. Growth charts in neonates, Curr Med Res Pract. (2016), http://dx.doi.org/10.1016/j. cmrp.2016.03.009
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26. Villar J, Giuliani F, Bhutta ZA, et al. Postnatal growth standards for preterm infants: the Preterm Postnatal Followup Study of the INTERGROWTH-21(st) Project. Lancet Glob Health. 2015;3(11):e681–e691. 27. Villar J, Cheikh Ismail L, Victora CG, et al. International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Lancet. 2014;384(9946):857–868.
28. Giuliani F, Cheikh Ismail L, Bertino E, et al. Monitoring postnatal growth of preterm infants: present and future. Am J Clin Nutr. 2016;103(2):635S–647S. 29. Grummer-Strawn LM, Reinold C, Krebs NF. Centers for Disease Control and Prevention (CDC). Use of World Health Organization and CDC growth charts for children aged 0–59 months in the United States. MMWR Recommen Rep. 2010;59 (RR-9):1–15.
Please cite this article in press as: Shrestha S, et al. Growth charts in neonates, Curr Med Res Pract. (2016), http://dx.doi.org/10.1016/j. cmrp.2016.03.009
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/cmrp
Review Article
Growth charts in neonates Sujit Shrestha, Anup Thakur, Sanket Goyal, Pankaj Garg, Neelam Kler * Department of Neonatology, Sir Ganga Ram Hospital, New Delhi, India
article info
abstract
Article history:
There has been a continuous effort to develop standard growth charts for neonates.
Received 16 January 2016
Reference growth charts based on cross-sectional intrauterine data were developed from
Accepted 17 March 2016
measurement of anthropometric parameters of neonates of different gestations at birth.
Available online xxx
Similarly postnatal charts for preterm neonates were developed based on longitudinal measurements of infant's parameters over intervals. Fetal–infant growth charts were
Keywords:
devised by combining cross-sectional intrauterine data and postnatal infant's longitu-
Growth charts
dinal parameters. Revised Fenton 2013 charts incorporating neonatal anthropometric
Neonatal
data look to be most adequate for preterm infants of 22 weeks gestation till 50 weeks
Fetal
post-menstrual age. These growth references describe how infants grew in certain time
Head circumference
in a defined population. There was a need of developing growth standard defining growth of healthy population in optimal conditions. WHO Multicentre Growth Reference Study charts were developed as growth standards describing the growth of healthy children from term gestation till 5 years of age. Intergrowth 21st growth chart is the new growth standards for preterm infants and looks promising in infants of gestation 33 weeks or more. # 2016 Sir Ganga Ram Hospital. Published by Elsevier, a division of Reed Elsevier India, Pvt. Ltd. All rights reserved.
1.
Introduction
Growth is described as a net increase in size or mass of tissues as a result of either multiplication of cells or increase in intracellular substance.1 Fetal growth is the most rapid phase of growth in humans and exponential growth occurs by six folds between 22 and 40 weeks.2 It is influenced by fetal, placental and maternal factors. Under normal environment, a fetus grows as per its inherent growth potential to an appropriate size newborn. After birth, baby's growth is
determined by genetic potential and various internal and external factors.1 Infants are in a continuous process of growth. It is important to monitor the growth of infants to detect any deviation from normal. During hospital stay, a rapid change in weight may occur due to fluid overload or due to catch-up growth. Low gain may be due to inadequate nutrition or concurrent illnesses. Growth faltering in neonatal period can be due to faulty feeding, infections, cold stress, anemia and metabolic disturbances.3,4 Growth monitoring also helps in identifying babies at high risk of having poor neurodevelopmental outcome. Higher linear
* Corresponding author. Tel.: +91 9811047391; fax: +91 1125861002. E-mail address: [email protected] (N. Kler). http://dx.doi.org/10.1016/j.cmrp.2016.03.009 2352-0817/# 2016 Sir Ganga Ram Hospital. Published by Elsevier, a division of Reed Elsevier India, Pvt. Ltd. All rights reserved.
Please cite this article in press as: Shrestha S, et al. Growth charts in neonates, Curr Med Res Pract. (2016), http://dx.doi.org/10.1016/j. cmrp.2016.03.009
CMRP-172; No. of Pages 6
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current medicine research and practice xxx (2016) xxx–xxx
growth,5 weight gain and head growth are associated with better neurodevelopmental outcome including decreased incidence of cerebral palsy especially in extremely low birth weight babies.6 An important tool for growth monitoring in neonates is growth charts. Two common types of growth charts are 'growth references' and 'growth standards'. A 'growth reference' is a statistical summary of anthropometry in a reference group of children, whose health status is not taken into consideration.7 These charts are descriptive and show how children grow rather than how they should grow.8 A 'growth standard' is essentially the same as a growth reference except that the underlying reference sample is selected on health grounds. It is a prescriptive model representing a healthy pattern of growth and shows how the child should grow. Standard charts have the ability to diagnose overweight and obesity early and also avoid over diagnosis of undernutrition.7,8
2.
Neonatal growth charts
Historically, the idea of plotting a child's anthropometric parameters on a chart to illustrate the pattern of growth was first conceived by Count Philibert de Montbeillard of France in the 18th century. He plotted his son's height every six month from birth till the age of 18 years. Henry Bowditch was the first to use the centiles to describe the growth of Massachusetts children in 1891.7 Lubchenco's chart was amongst the first intrauterine growth chart to be widely used in neonates. It also classified newborns based on size at birth.9 Over last five decades, number of standard and reference charts have been developed for monitoring growth of term and preterm neonates.
2.1.
Reference growth charts
Reference growth charts used in preterm infants are: A. Intrauterine growth charts: Intrauterine growth charts are those that are derived from data of anthropometric measurements of preterm infants of different gestational age at birth. Available intrauterine charts are Lubchenco (1966), Usher and McLean (1969), Brenner (1976), Arbuckle (1993), Alexander (1996) and Kramer (2001).10 The drawbacks of these intrauterine charts are that they are based on small sample size and are not gender specific. Most of these charts used last menstrual period (LMP) to estimate gestation age instead of first trimester ultrasound (USG), which is less reliable.11 These charts are cross-sectional and lack the ability to describe longitudinal fetal growth.12 There are serious concerns about using them as standards, as preterm infants are different from fetus.10 Lubchenco charts (1948–1961) based on population of around 4700 newborns having gestation age from 26 to 42 weeks was one of the most widely used intrauterine growth charts. It was based on a multi-centric retrospective study, which included both term and preterm infants. Weight, length and head circumference were retrieved and smooth
growth curves were developed. Battaglia and Lubchecho were the first to describe newborns as small for gestation age, appropriate for gestation age and large for gestation age.9,13 The drawbacks of these charts are that they are based on population of only one country (USA) and included population of high altitude which are more likely to be growth restricted.14,15 B. Postnatal growth charts: These growth charts are based on longitudinal measurements of parameters of infants as they grow and as such provide actual postnatal pattern of infant's growth. Growth chart developed from these data as such cannot be prescriptive, as defining a healthy preterm is not possible.10 Postnatal growth charts include Dancis 1948, Infant Health and Development Program (IHDP) 1985, Shaffer 1987, Wright 1993, Berry 1997, Ehrenkranz 1999. These charts demonstrated the weight loss pattern after birth, regain of birth weight and subsequent growth.16,17 One of the popularly used postnatal charts was charts by Ehrenkranz (1999). It was based on a multicentric prospective cohort study from 12 centers based in USA and included 1660 infants with birth weights between 501 and 1500 g admitted within 24 h of age. Longitudinal data on weight, length, head circumference and mid-arm circumference were measured from birth until discharge, transfer, death, age 120 days, or a body weight of 2000 g. The strength of these charts is that they consist of a large, heterogeneous population of very low birth weight infants and included infants, who received more advance treatments such as surfactant replacement therapy, antenatal steroid and early aggressive nutritional regimens. These growth curves may be used to understand postnatal growth better and to identify infants developing morbidities affecting growth such as bronchopulmonary dysplasia. Drawbacks are that it is based on a small sample size and derived from population of a single country.18 Another significant shortcoming of use of this chart in practice is that it only provides a single line trajectory and not major centiles. C. Fetal–infant growth charts: These charts are constructed by merging two sets of reference data: cross-sectional data of anthropometric measurement of preterm infants at birth and postnatal longitudinal anthropometric data of term infants. Therefore, these charts permit growth comparison with fetus first and then to term standards. The advantage of using fetal–infant growth chart is that it allows to assess if a preterm neonate is achieving catch up growth or not.17 Examples are – Babson and Benda charts 1967, Fenton chart 2003 and Fenton charts 2013.2,19,20 Babson and Benda obtained anthropometric data of infants of mostly Caucasian population, with gestation age 27 to 44 weeks born between 1959 and 1966. It was popularly used but had limitations of not including neonates of lower gestation and had 500 g weight interval increments. This made precise plotting difficult.19 Fenton in 2003, updated the Babson–Benda charts and created new chart that could be used from gestation 22 weeks to 50 weeks. It allowed comparison of growth of a preterm infant with that of fetus initially starting as low as 22 weeks till 36 weeks and then later with term infants upto
Please cite this article in press as: Shrestha S, et al. Growth charts in neonates, Curr Med Res Pract. (2016), http://dx.doi.org/10.1016/j. cmrp.2016.03.009
CMRP-172; No. of Pages 6
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current medicine research and practice xxx (2016) xxx–xxx
Table 1 – Data sources used by Fenton in 2013 charts. Data source
Voight 2010
Olsen 2010
German perinatal survey
Pediatrix Medical Group hospital
Sample size N < 30 weeks Dates Data
23,000,000 14,146 1995–2000 Weight
Gestational assessment
USG 8–14 weeks and Naegle's rule
130,111 11,377 1998–2006 Weight, head and length Clinical assessment
Kramer 2001
Robert 1999
Canadian Australian national file national perinatal statistical unit
Bonellie 2008
Bertino 2010
Scottish maternity data collection
Italian neonatal study
676,605 3247 1994–1996 Weight
734,145 3193 1991–1994 Weight
100,133 2053 1998–2003 Weight
Early USG
Dates, prenatal or postnatal assessment
Clinical assessment based on USG, LMP
45,462 623 2005–2007 Weight, head, length USG 1st trimester
Table derived from Fenton and Kim.2
50 weeks. Data from studies including large population of newborns were used. Curves based on large preterm population were obtained but these charts were not sex specific and were designed for plotting as completed gestation weeks. Moreover the methodological quality and heterogeneity affected its validity.20 In 2013, revised Fenton charts were published. These charts were based on large preterm birth sample size of approximately 4 million infants. Data between 1991 and 2007 from developed countries (Germany, Italy, United States, Australia, Scotland and Canada) were included (as shown in Table 1). Advantages of these charts are that they include data from recent population based surveys and are sex specific. It can also be used to assign size for gestational age up to 36 weeks. Besides these, the curves are equivalent to the WHO growth curves at 50 weeks of post-menstrual age (PMA) (10 weeks post-term age) and therefore after this age WHO curves can be used. The chart is also advantageous as it enables to plot growth parameters of infants in between weeks and not as completed weeks. Apart from the studies mentioned in Table 1, data of 882 term babies were obtained from WHO Multicentre Growth Reference Study (MGRS)21 to smoothen the curves. The drawbacks are that Fenton 2013 is a growth reference and not a growth standard.2 Data plotted in 2013 Fenton Chart should be interpreted with caution in two aspects. First, similar to Fenton 2003, it does not address the physiological postnatal loss of body water after birth. Further, different centers used variable methods for measurement of crown-heel length, making its reliability doubtful. Another criticism is that Fenton used data of term babies to smoothen some portion of the chart used for preterm babies.22 However, this portion of curves between 37 and 50 weeks was later validated in another study where data disjuncture occurred by comparing them using weight gain patterns of contemporary preterm infants.23 Fenton growth curves 2013 for girls (Fig. 1) and boys from 22 to 50 weeks are available from http://www.ucalgary.ca/fenton/ 2013chart. Peditools.org is an online clinical tool available for easier calculation of centiles and z score as described by Fenton (Fig. 2).24 (Available at http://peditools.org/fenton2013.)
2.2.
Standard growth charts
The WHO growth standard 2006 for children are based on data from the WHO MGRS, conducted during 1997–2003 in six different countries of different continents including India. Data were based on both developed and developing nations. As per standard recommendation, the population sample included only full term breast fed infants whose growth was not restrained by socioeconomic status. Population of high altitude (>1550 m), infants born to mothers who smoked and those with perinatal complications were excluded. The growth curves for children aged below 24 months were based on the
Fig. 1 – Fenton fetal infant growth chart 2013, chart for girls.
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Fig. 2 – Software for calculation of z score and centile of Fenton chart 2013.
longitudinal component of MGRS. In the first 2 months data were collected at birth, 1 week, and every 2 weeks, then monthly till 12 months age and bimonthly from 14 to 24 months. On the contrary, the curves for children from 24 to 59 months were based on the cross-sectional component of MGRS. However the data in both the components were collected in the same community. To eliminate the effect of overweight, infants whose weight measurements were more than 2 standard deviations above the study median were excluded from the analysis.21 Unlike previous charts, WHO charts are growth standards, prescriptive in nature and also delineates children with obesity. These standards have been used by 125 countries. The main drawback is that, the WHO charts do not address babies of preterm gestation. WHO charts have been used in premature neonates after they reach 40 weeks PMA.2 The Intergrowth-21st Project was initiated by International Fetal and Newborn Consortium with the aim to produce new prescriptive standards describing normal fetal and newborn growth. Data were collected from 8 geographically different areas. Countries included were China, India, Italy, Oman, Brazil, Kenya, UK and USA. The study objectives were to generate international growth standards based on fetal growth from early pregnancy: Fetal growth longitudinal study (FGLS), standards for postnatal growth of preterm: preterm postnatal follow-up study (PPFS) and to determine newborn size at birth: newborn cross-sectional study (NCSS). Both LMP and USG combined over a time by a two stage process were used as a measure to ascertain gestation age. FGLS included anthropometric data of fetus from 14 weeks gestational age to birth for monitoring fetal growth clinically and by USG in a healthy population. Standard fetal growth curves were constructed based on USG for occipito-frontal diameter, head circumference and abdominal circumference, in addition to biparietal diameter and femur length. It is devised to be used for the clinical interpretation of routinely taken USG measurements. Of 4607 pregnant women enrolled
in FGLS, 224 went on to have preterm delivery.25 For PPFS, all preterm newborns of more than 26 weeks and less than 37 weeks were followed post-delivery for evaluation of postnatal growth. A total of 201 eligible preterm newborns from FGLS who met criteria of healthy or stable preterm were included. Standards for postnatal growth in preterm infants were obtained for weight, length and head circumference that can be used for assessment up to 64 weeks PMA.26 In the NCSS, a total of 20,486 eligible women were enrolled between May 2009 and August 2013. Weight, length and head circumference of all newborn infants whose mothers were enrolled in FGLS and those born within the Intergrowth-21st geographical areas during a fixed period of 12 months (FGLS-like population) were measured within 12 h of birth. Centile curves for 3rd, 10th, 50th, 90th, and 97th were obtained according to gestational age and sex. Prescriptive international anthropometric standards to assess newborn size from 33 to 43 weeks gestation were obtained from this study.26,27 Characteristics of these new charts are that it bridges gaps in clinical and population assessments for fetuses, neonates and infants through provision of similar instruments to monitor child growth continuously from early prenatal life up to the age 5 years. The standards obtained are populationbased, multiethnic, multi-country and sex-specific and they arise from a prospective study. Across all the eight study sites, not only a uniform research method and same protocol was used but also accurate gestational age estimation was ensured by 1st trimester USG. The methodology was further strengthened by use of identical equipment, training, a centralized electronic data management system and close monitoring of staff. Therefore, the standards are prescriptive and describe the optimum size in newborn infants without congenital abnormalities. Software is also made available for clinical and epidemiological use to calculate z scores and centiles (http://intergrowth21.ndog.ox.ac.uk/en/ ManualEntry). Standard charts obtained from PPFS charts used to assess preterm babies up to 64 weeks PMA overlapped
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with WHO MGRS chart.26 Limitations were that despite a large sample size, there were relatively few early preterm births below 33 weeks for PPFS study. In NCSS the lower limit of the curves was set at 33 weeks of gestation, because it was not possible to enroll preterm below this gestation age with very strict criteria.26,27
6.
7.
3.
Conclusion
With the increase in preterm survival, the concern regarding the use of appropriate growth chart to assess preterm growth is increasing. Therefore, there is a continuous effort to develop a standard growth chart for preterm infants, which can be used with confidence across all gestations and population. Intrauterine growth charts such as Lubchenco chart cannot be used for longitudinal assessment of growth. Ehrenkranz charts were developed for longitudinal growth monitoring of preterm infants but the study had a small sample size and do not provide gestation specific centiles. Intergrowth-21st postnatal growth standard for preterm infants was devised to address this issue and create a preterm postnatal growth standard from a prospective cohort from different geographical areas making them the recommended charts for neonates with gestation week 33 or more.28 However, as it had less number of infants below 33 weeks (28 infants) they may still not be useful in infants of lower gestation. Though Fenton charts 2013 are reference charts for preterm infants and lack standard prescriptive benefits, they still seem to be popular for preterm infants because they include data from 4 million preterm infants, allows precise sex specific plotting and smooth transition to WHO MGRS 2006 growth standards charts and can be used for preterm babies from 22weeks till 50 weeks PMA. We emphasize that for term infants, WHO MGRS 2006 growth charts should be used.29 As WHO MGRS charts are being widely used and the Intergrowth-21st charts showed reproducible results, it is expected to be accepted worldwide as well. However, these charts are still in process of implementation.
8. 9.
10. 11.
12.
13.
14.
15.
16.
17. 18.
19.
Conflicts of interest
20.
The authors have none to declare.
21.
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26. Villar J, Giuliani F, Bhutta ZA, et al. Postnatal growth standards for preterm infants: the Preterm Postnatal Followup Study of the INTERGROWTH-21(st) Project. Lancet Glob Health. 2015;3(11):e681–e691. 27. Villar J, Cheikh Ismail L, Victora CG, et al. International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Lancet. 2014;384(9946):857–868.
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Please cite this article in press as: Shrestha S, et al. Growth charts in neonates, Curr Med Res Pract. (2016), http://dx.doi.org/10.1016/j. cmrp.2016.03.009