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Normal and Abnormal Growth in Childhood
Essentials
- An assessment of a child's growth should always be based on long-term observation and plotting of growth charts, which must be updated and consulted regularly.
- The growth of the child should be assessed at every scheduled routine check-up visit at a child health clinic or at school health care and, if needed, at a medical consultation.
- The growth charts and screening rules presented in this article are based on the principles and data that have been in use in Finland for a considerable length of time. New charts have been defined in 2010-2011 and integrated into several electronic growth chart applications.
- Normal growth of a child is characterised by consistency.
- The follow-up of the growth aims at diagnosing in good time all conditions and diseases that affect growth.
- Possible psychosocial consequences of growth disturbances should also be anticipated and treated accordingly. In some cases, growth may be accelerated even in the absence of a specific treatable cause.
- Consult also national and local guidelines regarding the management of children's growth disturbances and obesity. A specialist should be consulted early whenever a child's growth is abnormal and requires assessment and further management.
- See also article Overweight and obesity in children Overweight and Obesity in Children.
Definitions
Current and expected length/height-for-age
- Length/height-for-age (L/A) removes age and gender differences. A current L/A expresses deviation from the average in standard deviation (SD) units, and a score of 0 represents an average height for age and gender.
- Growth is consistent when the L/A score remains almost unchanged.
- An expected L/A score corresponds to a family-specific average height (mid-parental target height).
- The expected L/A score is shown in the electronic growth charts. It can also be calculated with the formula [(average of parents' height in cm)-171)]/10.
- E.g. if the father's height is 185 cm and the mother's 165 cm the expected L/A score of the child is [(185+165)/2-171)]/10 = 4/10 = +0.4 SD.
Weight-for-height, BMI-for-age and ISO-BMI
- E.g. in the Finnish growth charts, the weight of children less than 2 years of age is assessed in relation to the child's height (weight-for-height), because there is only little experience on the use of body mass index (BMI) in this age group.
- Weight-for-height is expressed as a percentage deviation from the median weight of children of the same gender and with the same height.
- In children over 2 years of age, weight can be assessed either by weight-for-height or by age- and gender-specific BMI (BMI = weight in kilograms divided by the square of height in metres; unit kg/m2 ). Changes in BMI are evaluated in relation to the normal values (expressed in SDS units).
- BMI in a child can be transformed to the corresponding adult ISO-BMI that reflects the child's BMI as an adult. In interpreting the ISO-BMI values, the adult cut-off points for overweight (25 kg/m2 ) and obesity (30 kg/m2 ) are used (ISO-BMI calculator Body Mass Index (Iso-Bmi) Calculator for Children).
Tempo of growth, growth reserve, skeletal maturation and bone age
- The concept tempo of growth refers to the duration of the various stages of growth and development. The developmental years in girls last on average two years less than in boys.
- Growth reserve denotes an individual's genetic remaining growth potential under favourable conditions.
- Skeletal maturation is determined most objectively by measuring the bone age, i.e. a gender-adjusted median age that corresponds to the child's bone maturity stage.
- The bone age denotes skeletal maturity in comparison with chronological age. Its interpretation requires experience.
Body proportions and sitting height
- Fetal growth mainly involves the growth of the head and trunk.
- Growth in childhood principally affects the limbs, and the pubertal growth spurt again involves truncal growth.
- Sitting height (picture ) describes the ratio between the lower limbs and the trunk. It is determined when investigating the aetiology of abnormal growth. Sitting height is expressed as a percentage of the total height T1.
Normal percentage of sitting height (95% confidence interval) vs. total height
Age (years) | Boys and girls | Age (years) | Boys | Girls |
---|
0.25 | 60.0-72.5 | 9.0 | 50.5-55.5 | 50.7-55.8 |
0.50 | 60.7-71.4 | 10.0 | 49.9-54.9 | 50.2-55.5 |
1.0 | 60.3-68.2 | 11.0 | 49.5-54.6 | 50.0-55.3 |
1.5 | 59.3-66.1 | 12.0 | 49.1-54.1 | 49.9-55.1 |
2.0 | 58.3-64.2 | 13.0 | 48.8-53.8 | 50.1-55.0 |
2.5 | 57.2-62.5 | 14.0 | 48.8-53.7 | 50.5-55.0 |
3.0 | 56.1-61.3 | 15.0 | 48.9-53.7 | 51.1-55.1 |
4.0 | 54.5-59.5 | Adult | 51.1-55.9 | 51.6-56.4 |
5.0 | 53.4-58.3 | | | |
6.0 | 52.5-57.3 | | | |
7.0 | 51.8-56.6 | | | |
8.0 | 51.2-56.1 | | | |
Phases of growth
- A child's growth after birth may be divided into three phases which overlap to some extent: infancy, childhood and puberty. Each phase has its own regulatory mechanisms and disorders.
- In the infancy phase the growth velocity is high and continues with sharp deceleration up to the age of about 2-3 years.
- The most important requisite for the normal progress of the infancy phase is an adequate amount of high-quality nutrition.
- In the infancy, the child's height growth settles into a growth channel which is then consistently followed during the childhood.
- If the child's L/A score at birth markedly differs from the score corresponding to the final height there may be significant shifts in the growth channel.
- The childhood phase begins around the age of 6 months, i.e. whilst the infancy phase is still continuing, and continues with slowly decelerating velocity throughout the entire growing years.
- In the childhood phase, the child's growth is consistent with no marked changes in the L/A score.
- Many children show a mild transitory acceleration of growth velocity between 6 and 8 years of age. This is known as the mid-childhood growth spurt.
- Growth velocity is at its slowest immediately prior to the pubertal growth spurt.
- In practice, a child should grow annually from 4 to 7 cm.
- The puberty phase has three stages: slow growth in early puberty, a growth spurt lasting for approximately two years which is followed by final deceleration and cessation of growth.
- Early puberty will bring the growth spurt forward, and the growth chart will show an upward deviation.
- If puberty appears late, the child will continue to grow with the decelerating velocity of childhood growth, and the growth chart will show a downward deviation.
Length/height measurements and growth charts
- Appropriate equipment and the correct measuring technique are the cornerstones of height monitoring.
- It is important to complete the section, provided in the growth charts, for personal and family history (e.g. measurements at birth, height of the parents, parents' developmental pattern).
- Ethnic background should be taken into account when assessing growth. In immigrants, growth should primarily be assessed using the growth charts of the country of origin. For practical reasons, it is often the charts of the current country of living that have to be used, and the ethnic background is taken into account when interpreting the findings.
- It is advisable to use condition- or disease-specific charts if available (e.g. in Down's syndrome Down's Syndrome).
Interpretation of the charts
- If the measurement suggests a deviation from the child's growth pattern, the correctness of the actual measurement and of the chart entry should be initially checked.
- If a deviation from the growth pattern is confirmed with repeated measurements, the reason for the growth disturbance should be sought. The child's overall health status should also be checked.
- A concurrent change both in the height and weight is often suggestive of an illness, particularly when a discrepancy is observed: weight increases while growth slows down, or vice versa.
- If the growth deviation is associated with signs and symptoms of an illness, medical intervention is needed urgently.
- If several measurements confirm that the screening thresholds for height are broken, specialist intervention is warranted, even if routine investigations were within the normal range.
- To be noted in the interpretation:
- The growth of an infant less than 1 year of age should be interpreted with care. Final settling into one's own growth channel may in a healthy child cause a significant shift on the growth chart. Weight may fluctuate particularly according to bladder and bowel functioning. Repeated infections will also quickly affect an infant's weight. A single measurement on its own is usually without any value; long-term monitoring of growth is already of importance at this early age.
- Usual screening rules do not apply for adolescents, and growth must be related to the pubertal development and overall status of the adolescent.
Length/height and weight screening
- Growth screening aims at identifying children who require further investigations in relation to growth.
- The screening rules based on the new growth charts applied in Finland are mathematically complex and can only be used in electronic applications. The rules described below can be applied if such an electronic application is not available.
Length/height screening
- Screening threshold for length/height is broken if the deviation from expected L/A score is ± 2.3 SD, or ± 2.7 SD from the age-adjusted average length/height if the expected L/A score is not known. The screening threshold is also broken if the deviation of the L/A score during a set period of time exceeds the limits for acceptable deviation (tables T2 and T3).
Acceptable deviation of the L/A score (SD) in children less than 2 years of age
Age, years | During the preceding 0.25 years | During the preceding 0.5 years | During the preceding 1.0 years |
---|
0.25 | 1.7 | | |
0.5 | 1.1 | 2.1 | |
0.75 | 0.9 | 1.6 | |
1.0 | 0.9 | 1.5 | 2.3 |
1.25 | 0.8 | 1.4 | 1.9 |
1.5 | 0.7 | 1.3 | 1.7 |
1.75 | 0.6 | 1.2 | 1.6 |
2.0 | 0.6 | 1.0 | 1.5 |