Agrowth chart is used bypediatricians and other health care providers to follow a child's growth with age. Growth charts have been constructed by observing the growth of large numbers of healthy children over time. Theheight,weight, andhead circumference of a child can be compared to the expected parameters of children of the same age and sex to determine whether the child is growing appropriately. For each parameter, a set ofgrowth curves are graphed for themedian value (the "middle" value, at 50percentile), lower and upperquartiles (bottom and top 25%), as well the lower and upperdeciles (bottom and top 10%).
Growth charts can also be used to predict the expected adult height and weight of a child because, in general, children maintain a fairly constant growth curve. When a child deviates from his or her previously established growth curve, investigation into the cause is generally warranted. Parameters used to analyze growth charts include weight velocity (defined as rate of change in weight over time), height velocity (defined as rate of change in stature over time), and whether someone's growth chart crosses percentiles. For instance, endocrine disorders can be associated with a decrease in height velocity and preserved weight velocity while normal growth variants are associated with a decrease in height and weight velocity that are proportional to each other. It's important to note that other parameters are more commonly used such as waist circumference for assessing obesity and skin fold difference for assessing malnutrition. Growth charts can also be compiled with a portion of the population deemed to have been raised in more or less ideal environments, such as nutrition that conforms to pediatric guidelines, and nomaternal smoking. Charts from these sources end up with slightly taller but thinner averages.[1]
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Growth charts are different for boys and girls, due in part to pubertal differences and disparity in final adult height. In addition, children born prematurely and children with chromosomal abnormalities such asDown syndrome andTurner syndrome follow distinct growth curves which deviate significantly from children without these conditions. As such, growth charts have been created to describe the expected growth patterns of several developmental conditions. Since there are differences in normal growth rates between breastfed and formula-fed babies,[2] the World Health Organization growth charts, which better reflect the growth pattern of the healthy, breastfed infant, are considered the standard for U.S. children under age two.[3]
The growth chart was first developed by theNational Center for Health Statistics (NCHS) in 1977 to clinically analyze child development. The 1977 growth chart was subsequently used by theWorld Health Organization for dissemination to healthcare systems abroad. In order to accommodate for heterogenous populations internationally, the WHO made an effort to gather data from different regions in every continent. Data used to calculate the CDC's growth chart percentiles was accumulated periodically since the 1960s by theNational Health and Nutrition Examination Survey. Updated and more comprehensive data was later used to revise the existing growth chart and construct the 2000 CDC growth charts. The revised growth charts include revision of the 14 existing charts as well as introduction of 2 new BMI-for-age charts.[4]
Mid-parental height (MPH) is often used to predict the target height of an individual based on the heights of the two biological parents. It can be used to calculate thetarget height (TH) for children. MPH is given as simply the mathematical average of the heights of the child's parents:MPH is unisex; however, boys need an upward correction, while girls need a downward correction. In view of an average height difference between adult men and women of 13 cm (5.1 in),TH is usually given as
Alternatively,TH can be expressed in standard deviation scores (SDS), where thetarget height (SDS),THSDS, is the average of the mother's height SDS and the father's height SDS. However, this calculation is incorrect as it needs adjustment to mid-population height. It is suggested to use theconditional target height orcTH_SDS with a correction factor of 0.72:[5]
Velocity[note 1] (of growth) is another quantity that is used to quantify growth curves. It can be used for both height and weight. In the equation providedq is either weight or height,t represents time, andΔ represents change over a defined interval. Growth velocity is defined as follows:[6]
Despite certainlimitations,body mass index (BMI) is still a useful quantification when used for statistical analysis that can gauge level of obesity. It is defined as follows with the given clinical ranges.
Bone age is another useful metric that complements a physician's use of a growth chart. It is particularly useful in working up growth abnormalities and can indicate a delay in onset ofpuberty.
The combination of height and weight velocity can indicate underlying disease of genetic origin, endocrine cause, and/or delayed growth.
One of the most common growth disorders, a growth deficiency can be due to either familial short stature or constitutional growth delay (CGD). Familial short stature is indicative when one or both parents are of a short stature, and the height and weight percentiles are under the 5 percentile threshold.[7] The child will be concordant with the mean parental height, and the bone age should be normal. Constitutional growth delays are marked by low height and weight percentiles as early as the first 4–6 months following birth.[8]
A variety of genetic syndromes can result growth chart patterns with a typical pattern. Genetic diseases such asTurner's syndrome,Prader Willi, andNoonan syndrome can be marked by a less than 5th percentile height and weight since birth.[9][10][11] Other genetic disorders such asMarfan's syndrome andKlinefelter's syndrome are typically indicated by a height above the 90th percentile.[12][13]
A decrease of height velocity with retained or increased weight velocity can be indicative of endocrine disorders includinghypothyroidism,growth hormone deficiency, and excess ofglucocorticoids.
The CDC's growth chart is utilized from a population that consists of a representative population in the USA. Charts based on a specific race or ethnicity are not useful because of the growth chart progression can be attributed to socioeconomic factors.[14] WHO launched a revised growth in 2006 chart using children from Ghana, Oman, Norway, Brazil, India and the USA that substantiated the fact that growth is highly dependent on environmental factors.[15]
Growth spurts in children can be identified through the following observable indicators:[16]
Children may need significantly more sleep during growth spurts as their bodies work hard to grow and develop.
Your child may eat more than usual as their body requires extra nutrition to support rapid growth.
Clothes and shoes that fit well last month may suddenly become too tight or short.
Children may experience dental changes as part of their overall growth and development.
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