Frequently Asked Questions About the 2000 CDC Growth Charts
How can I get copies of the growth charts?
The clinical charts are available from the Clinical Growth Charts page and can be downloaded and copied. PowerPoint files of the growth charts, which can be modified with different logos, are also available on the PowerPoint Presentations of the Clinical 2000 CDC Growth Charts page. Growth charts formatted for the Women, Infants, and Children (WIC) program are available from the WIC website. In addition, The American Academy of Pediatrics (AAP) is selling copies of the growth charts and some pharmaceutical companies are distributing them.
What is a percentile?
Percentiles are the most commonly used clinical indicator to assess the size and growth patterns of individual children in the United States. Percentiles rank the position of an individual by indicating what percent of the reference population the individual would equal or exceed. For example, on the weight-for-age growth charts, a 5-year-old girl whose weight is at the 25th percentile, weighs the same or more than 25 percent of the reference population of 5-year-old girls, and weighs less than 75 percent of the 5-year-old girls in the reference population.
What is a z-score?
A z-score is the deviation of the value for an individual from the mean value of the reference population divided by the standard deviation for the reference population. Because z-scores have a direct relationship with percentiles, a conversion can occur in either direction using a standard normal distribution table. Therefore, for every z-score there is a corresponding percentile and vice versa.
My child is at the 5th percentile on a chart, what should I do?
If you are concerned about your child’s growth, talk with your child’s health care provider.
What growth charts are appropriate to use with exclusively breastfed babies?
In the United States, the WHO growth standard charts are recommended to use with both breastfed and formula fed infants and children from birth to 2 years of age (CDC, 2010). The WHO growth charts reflect growth patterns among children who were predominantly breastfed for at least 4 months and still breastfeeding at 12 months. These charts describe the growth of healthy children living in well-supported environments in sites in six countries throughout the world including the United States. The WHO growth charts show how infants and children should grow rather than simply how they do grow in a certain time and place and are therefore recommended for all infants (Dewey, 2004; WHO Multicentre Growth Reference Study Group, 2006).
The WHO growth charts establish the growth of the breastfed infant as the norm for growth. Healthy breastfed infants typically put on weight more slowly than formula fed infants in the first year of life (Dewey, 1998). Formula fed infants gain weight more rapidly after about 3 months of age. Differences in weight patterns continue even after complementary foods are introduced (Dewey, 1998).
What charts should be used for special populations?
The CDC has not evaluated the use of the WHO growth charts in premature or very low-birth weight infants. The 2000 CDC growth charts for the United States include data on low birth weight infants but do not include data on very low birth weight infants (VLBW; less than 1,500 grams). Alternate charts are available to assess the growth of VLBW infants. The most recent charts are those developed from data collected in the National Institute of Child Health and Human Development Neonatal Research Network Centers (Ehrenkranz, 1999). These charts extend to about 120 days uncorrected postnatal age or until a body weight of 2,000 grams is reached. A specific growth reference available for VLBW infants is the Infant Health and Development Program (IHDP) reference (Guo, 1996; Guo, 1997; Roche, 1997). The IHDP growth charts are an option for assessing the growth of VLBW infants from an age corrected for gestation of 40 weeks to 36 months. However, a limitation of the IHDP charts is that they are based on data collected in 1985, before current medical and nutritional care practices were being used. See the training module: Growth Charts for Children with Special Health Care Needs for information on assessing growthof low birth weight and premature infants.
A variety of health conditions affect growth status and there are specialized charts that may be considered for use with children affected by these conditions. See the training module: Growth Charts for Children with Special Health Care Needs for a discussion of these charts. These specialized growth charts provide useful growth references, but may have some limitations. Generally, they were developed from relatively small homogeneous samples and data used to develop the charts may have been obtained from inconsistent measuring techniques. For example, in some cases, chart reviews were used to collect data; in other cases, the measurement techniques were not clearly defined. In most cases, Body Mass Index (BMI)-for-age charts are not available for special conditions and have not been validated to use with children whose body composition might differ from that of typical children. For children aged 2 to 20 years, the CDC BMI-for-age growth charts would provide a useful reference to monitor weight in relation to stature.
Centers for Disease Control and Prevention. Use of the World Health Organization and CDC growth charts for children aged 0-59 months in the United States. MMWR Recomm Rep. 2010;59(RR-9);1-15. Accessed November 26, 2012.
Dewey KG, Cohen RJ, Nommsen-Rivers LA, Heinig MJ, for the WHO Multicenter Growth Reference Study Group. Implementation for the WHO Multicentre Growth Reference Study in the United States. Food Nutr Bull. 2004;25(suppl1):S84-S89.
WHO Multicentre Growth Reference Study Group. Assessment of differences in linear growth among populations in the WHO Multicentre Growth Reference Study. Acta Paediatr Suppl. 2006;450:56-65.
Dewey KG. Growth characteristics of breastfed compared to formula-fed infants. Biol Neonate. 1998;74(2):94-105.
Ehrenkranz RA, Younes N, Lemons JA, Fanaroff AA, Donovan EF, Wright LL, Katsikiotis V, Tyson JE, Oh W, Shankaran S, Bauer CR, Korones SB, Stoll BJ, Stevenson DK, Papile L. Longitudinal growth of hospitalized very low birth weight infants. Pediatrics. 1999;104:280-289.
Guo SS, Wholihan K, Roche AF, Chumlea WC, Casey PH. Weight-for-length reference data for preterm, low birth weight infants. Arch Pediatr Adolesc Med. 1996;150:964-970.
Guo SS, Roche AF, Chumlea WC, Casey PH, Moore WM. Growth in weight, recumbent length, and head circumference for preterm low-birthweight infants during the first three years of life using gestation-adjusted ages. Early Hum Dev. 1997;47:305-325.
Roche AF, Guo SS, Wholihan K, Casey PH. Reference data for head circumference-for-length in preterm low-birth-weight infants. Arch Pediatr Adolesc Med. 1997;151:50-57.