Human Growth and Development

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Continuing Education Activity

Evaluation of growth and development is a crucial element in the physical examination of a patient. A piece of good working knowledge and the skill to evaluate growth and development are necessary for any patient's diagnostic workup. The early recognition of growth or developmental failure helps for effective intervention in managing a patient's problem. This activity reviews the various aspects of human growth and development and highlights the interprofessional team's role in assessing the kids for growth and developmental delay.

Objectives:

  • Describe the stages of growth and development.
  • Review the factors affecting growth and development.
  • Outline the methods for growth measurements and standard screening tools for developmental assessment.
  • Explain how interprofessional collaboration and communication can improve patient outcomes when assessing a patient's physical development.

Introduction

In the context of childhood development, growth is defined as an irreversible constant increase in size, and development is defined as growth in psychomotor capacity. Both processes are highly dependent on genetic, nutritional, and environmental factors.  Evaluation of growth and development is a crucial element in the physical examination of a patient. A piece of good working knowledge and the skills to evaluate growth and development are necessary for any patient's diagnostic workup. The early recognition of growth or developmental failure helps for effective intervention in managing a patient's problem.

Stages in Human Growth and Development 

  1. Fetal stage: Fetal health issues can have detrimental effects on postnatal growth. One-third of neonates with intrauterine growth retardation might have curtailed postnatal growth.[1] Good perinatal care is an essential factor in promoting fetal health and indirectly postnatal growth.
  2. Postnatal stage: The process of postnatal growth and development happens together but at different rates. The growth occurs by discontinuous saltatory spurts with a stagnant background.[2] There are five significant phases in human growth and development,
    1. Infancy (neonate and up to one year age)
    2. Toddler ( one to five years of age)
    3. Childhood (three to eleven years old) - early childhood is from three to eight years old, and middle childhood is from nine to eleven years old. 
    4. Adolescence or teenage (from 12 to 18 years old)
    5. Adulthood

Factors Affecting Growth and Development 

The growth and development are positively influenced by factors, like parental health and genetic composition, even before conception.[3]

  1. Genetic factors play a primary role in growth and development. The genetic factors influencing height is substantial in the adolescence phase.[4] A large longitudinal cohort study of 7755 Dutch twin pairs has suggested that the additive genetic factors predominantly explained the phenotypic correlations across the ages for height and body mass index.[5] 
  2. Fetal health has a highly influential role in achieving growth and development. Any stimulus or insult during fetal development causes developmental adaptations that produce permanent changes in the latter part of life.
  3. After birth, the environmental factors may exert either a beneficial or detrimental effect on growth.[6]
    • Socioeconomic factors: Children of higher socio-economical classes are taller than the children of the same age and sex in the lower socioeconomic groups. Urbanization has positively influenced growth. The secular trend is observed in growth where the kids grow taller and mature more rapidly than the previous generation. This secular trend is observed significantly in developed countries like North America.
    • The family characteristics: Higher family education levels have a positive impact on growth. The inadequate emotional support and inadequate developmental stimulus, including language training, might cause growth and development deterioration. 
    • The human-made environment influences human growth and development significantly. Certain ongoing studies have proven the relationship of pollutants in sexual maturation, obesity, and thyroid function.[7] The excess lead exposure antenatally significantly associates with low birth weight. Noise pollution due to transportation sources also has an association with reduced prenatal growth. 
    • Nutrition 
      1. Malnutrition plays a detrimental role in the process of growth and development. 
      2. Deficiencies of trace minerals can affect growth and development.[8] Iron deficiency usually affects psychomotor development and does not affect growth. Zinc deficiency might cause growth retardation and developmental delay. Selenium, iodine, manganese, and copper also play a significant role. 
      3. Growth faltering or rapid weight gain in early childhood influences health in the later part of life. The diet in early childhood has a strong association with the likelihood of obesity later in life. 'Early Protein Hypothesis' shows that lowering the protein supply during infancy helps achieve normal growth and reduce obesity in early childhood.[9] This concept of the early protein hypothesis helps in improving the food products for children. 
  4. Genetic and environmental factors influence the growth and development in a perplexing interrelated pathway. Genetic and environmental risk factors are not mutually exclusive. Plasticity is the potential of a specific genotype to bring out diversified phenotypes in response to diverse environmental factors.[10] The developmental plasticity can happen from the embryonic stage to adolescence and can be passed onto the next generation. 
  5. Role of experience during early childhood: Exposure to adverse experiences in early childhood might hinder development. Profound neglect during early childhood can impair development. Children adopted before six months of age have similar development when compared to their non-adoptive siblings. If children adopted after six months have a high risk of cognition deficits, behavioral issues, autism, and hyperactivity.[11] Early intervention for children with adverse experiences is the pillar in healthy development.

Issues of Concern

Measurement of Growth

Anthropometry is the gold standard by which clinicians can assess nutritional status. The major anthropometric measurements for age up to 2 years are weight, length, weight for length, and head circumference. The major measurements used for children above two years are weight, height, body mass index (BMI), and head circumference for the 2-3 years age group. 

  1. Length or height: For children less than two years or children with severe cerebral palsy, the length is the ideal way of measuring stature. Length is measured by placing the child supine on an infant measuring board. For children aged more than two years, standing height is measured in the stadiometer after removing shoes. The supine length is usually 1 cm higher than standing height. Length and height can be documented to the closest 0.1 cm. For children with severe cerebral palsy or spinal deformities, upper arm length, tibial length, and knee height can be useful to assess stature.[12]
  2. Weight: The kids below one year are weighed on a scale after removing the clothes, shoes, diaper, and documented to the closest 0.01 kg. The kids outside the infancy phase should be measured without shoes, with little or no outer clothing, and documented to the closest 0.1 kg. 
  3. Head circumference or occipitofrontal circumference: Head circumference is assessed by measuring the largest area from the prominent site at the back (occiput) to the frontal prominence above the supraorbital ridge. Brain growth is maximum in the first three years of life, so head circumference is used in children less than three years.  It is measured as the maximum diameter through the supraorbital ridge to the occiput and documented to the closest 0.01 cm. Microcephaly is more than two standard deviations below the mean. Macrocephaly is more than two standard deviations above the mean. 
  4. Measure of adiposity:
    1. Body mass index (BMI) is a useful predictor of adiposity. BMI is calculated with formula,weight (kg) / height (m) squared. BMI is the single best indicator for detecting overweight or obesity
      • < 5th percentile - underweight 
      • 5th to 84th percentile - normal 
      • 85th to 95th percentile - overweight 
      • 95th to 98th percentile - obesity 
      • More than 99th percentile - severe obesity
    2. The weight to length ratio is an alternative for body mass index in predicting adiposity in less than two years. 
    3. Self-assessment of the hip to waist ratio can help to guide the measure of central adiposity,
    4. Triceps and subscapular skinfolds can also be a useful measure of adiposity.[13]
  5. Body proportions
    1. The upper segment to lower segment (U/L) ratio is 1.7 at birth, 1.3 at three years, and reaches 1.0 at greater than seven years. A higher U/L ratio is a feature in short-limb dwarfism.
    2. Arm span to height ratio is a fixed ratio across all ages. The ratio of more than 1.05:1 is suggestive of Marfan syndrome.[14]
  6. Sexual maturity: Tanner's stage can be used to assess sexual maturity.
  7. Skeletal maturity: Bone age can be determined by doing Hand & Wrist radiographs from 3 to 18 years of age. 
  8. Dental assessment: Primary tooth eruption begins with the central incisors at six months. No single tooth by 13 months of age is of concern. Permanent tooth eruption starts at six years of age and continues up to 18 years of age. 

Growth Velocity 

The growth velocity is different at different stages of life. Also, different tissues grow at different rates at the same stage of life. The lymphoid tissues can exceed adult size at six years of age. Girls are taller than boys at 12 to 14 years, but later they will not grow taller than their boy's counterpart. Growth velocity is maximum during infancy and adolescence. The head circumference reaches closer to adult size by six years of age. The prepubertal height velocity of less than 4 cm per year is of concern. During puberty, the height velocity is 10 to 12 cm per year in boys and 8 to 10 cm per year in girls. The prepubertal weight velocity of less than 1 kg per year is of concern. Weight velocity is highest during puberty, up to 8 kg per year.

Stages of Development

Development is a continuous process from neonatal to adulthood. Though the growth ceases after adolescence, adolescence is not the end for development. Each developmental stage has a new set of challenges and opportunities. 

  1. Infancy: Development progress in cephalo-caudal direction and also from the midline to the lateral direction.  A three to four-month variation can be there in achieving the developmental milestone. Social development is a cortical function that develops earlier than motor skills. Lack of social smile by four weeks is of concern. At birth, the infant is equipped with primitive reflexes. Certain primitive reflexes help in the normal physiology of infants. Sucking and rooting reflex helps inefficient feeding. Most of the primitive reflex disappears to facilitate the mature development process. For example, the grasp reflex disappears by six months, and the child develops mature grasp development from 6-12 months.
  2. Early and late childhood: Between ages 1 and 3 years, locomotion and language are crucial. The best predictor of cognitive function is language. Fine motor skills are related to self-help skills. The most common development in early childhood is to establish self-identity. A child may have independent existence by three years of age. The kids learn independent existence skills like feeding behavior, toilet training, and self dressing during this stage of early and late childhood. Questioning skills develop during early childhood development.   
  3. Adolescence: Adolescence is hallmarked by puberty changes, which occur two years earlier in females than in males. Puberty changes are assessed using the Tanner staging. Acceptance of a new body and separation from home, and establishing oneself as an independent adult in society are the significant challenges in puberty.

Psychosocial Development 

Erikson has postulated eight stages of psychosocial development.

  1. Trust and mistrust in infancy (< 1 year): Infants develop trust with a warm response from the caretaker.  
  2. Autonomy and doubt in the toddler age group ( one to three years):  Children feel autonomous if caregivers encourage independence. Otherwise, they will doubt their abilities.
  3. Initiative and guilt in the preschool age group (three to six years): By imaginative play, kids experiment with their ambitions. If parents do not encourage their initiative, the kids will feel guilt.  
  4. Industry and inferiority in early school years: In school, children learn to work as a group. They will have inferiority feelings if the peer environment is hostile.
  5. Identity and role confusion in adolescence: Self-identity is a significant development during adolescence. 
  6. Intimacy and isolation in early adulthood: Those who cannot establish relationships or intimacy are prone to be socially isolated.
  7. Generativity and stagnation in middle adulthood: Parenting is the best example to guide the younger generation. 
  8. Ego integrity and despair in late adulthood: People who are not satisfied with what they did during their lifetime will be in despair.

Clinical Significance

Understanding normal growth and development milestones are important for a clinician evaluating pediatric patients. It isn't easy to recognize aberrance if you are not familiar with normal. By using growth charts and doing the developmental screening, oftentimes, challenges in care can be identified early.

Growth Charts

  • The CDC charts include children raised in a variety of nutritional conditions in the United States. In the CDC charts, the normal range between 5th and 95th percentiles. 
  • The WHO growth chart describes children from birth to five years raised under optimal environmental conditions. The normal range is expressed as a Z score between -2.0 and +2.0, corresponding to 2 and 98 percentiles. Z-scores are the number of Standard deviations from the mean.
  • The WHO growth charts represent a growth standard, whereas the CDC growth chart represents a growth reference. WHO growth charts are used for children under two years of age, and the CDC growth charts are used in children for more than two years. 
  • When using the WHO charts, the prevalence of short stature and obesity is similar to the CDC charts, but the underweight prevalence was lower than the CDC charts.[15][16]
  • Preterm infants 
    1. During the stay in the neonatal intensive care unit, preterm growth charts like Fenton growth charts are used for all preterm infants less than 37 weeks gestational age. Fenton charts can be used from 22 weeks gestational age and up to ten weeks post-term.
    2. WHO charts are useful to monitor the growth of preterm infants less than 37 weeks after discharge. The corrected postnatal age is used for up to two years. Corrected age for preterm kids is calculated as actual age in weeks - (40 weeks - gestational age at birth in weeks).[17]

Developmental Screening 

Only 20% of the children with developmental delay in the United States receive early intervention before three years. Early intervention is useful in high-risk children to improve their cognitive and academic performance. Less than 50 % of clinicians are only using standardized screening tools in practice. Time constraints, lack of training are essential barriers in using the developmental screening tool. The Ages and Stages Questionnaire (ASQ), the Parents' Evaluation of Developmental Status, and the Child Development Inventory are standard screening tools used in practice. ASQ tool can be used for up to 66 months. The PEDS tool can be used up to eight years of age.  Gross and fine motor milestones are assessed at every well-child visit in the first four years. Standardized developmental assessments using ASQ are mandatory at 9, 18, and 24 or 30 months.[18] 

The clinician may screen more frequently if there are risk factors like prematurity, lead exposure, or low birth weight. Autism screening needs to be done at 18 and 24 months of age. If the screening tool reveals developmental delay, the child needs referrals to developmental pediatricians. Children up to three years with developmental delay are referred to early intervention programs, and children above three years of age are referred to special education services. 

Red Flags in Growth and Development 

  • Red flag signs in motor development are persistent fisting for more than three months, the persistence of primitive reflexes and rolling before two months, and hand dominance before 18 months. 
  • No babbling by twelve months, no single words by sixteen months, no two-word sentences by two years, and loss of language skills are red flags.
  • Children whose height or weight readings below the 5th percentile, above the 95th percentile, or cross two major centile lines need further evaluation.

Enhancing Healthcare Team Outcomes

The health care team should understand the developmental stages that their patients go through during early childhood. We should increase the awareness of health care professionals about the importance of standardized growth monitoring and the appropriate use of growth charts. Also, they need adequate training for using standard developmental screening tools.

Every clinician and nurse managing pediatric patients should have appropriate awareness of referral service to early intervention for eligible patients. Interprofessional collaboration between clinicians, mid-level practitioners, and nurses can improve patient outcomes as developmental delays require prompt intervention when caught, and earlier is always better. Children up to three years with developmental delay are referred to early intervention programs, and children above three years of age are referred to special education services.


Article Details

Article Author

Palanikumar Balasundaram

Updated:

6/10/2021 7:55:47 AM

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