KIN 4512 Module 4

ASSESSMENT OF PRENATAL GROWTH

- assess the health/condition of the baby in advance - ultrasound (most common) - 3D images (using new imaging software)

Growth and Aging Change Individual Constriants

-A wealth of factors combine to influence patterns of growth and aging >Factors which can or cannot be changed. -Individual constraints cannot be changed. -Task and some environmental constraints can be changed >Educators and therapists can make task developmentally appropriate >To shape abilities, overcome disabilities

Why is the study of physical growth important to us?

-Physical size CHANGES motor skill acquisition and performance. -Determine typical growth patterns >Deviation from normal trajectory may be first indicator of problems-- physical, psychological, etc. -Determine constraints on motor development and performance

DIFFERENT CAUSES OF ABNORMAL PRENATAL DEVELOPMENT

1. Genetic causes 2. Teratogens 3. Extrinsic factors -all refer to "congential defects" - anomalies present at birth, regardless of their cause

Summary: Growth, Maturation, and Aging

1.Prenatal development •Primarily influenced by genetic and extrinsic factors •Most extrinsic factors are influential through the nourishment system 2.Growth abnormalities can be caused by genes, environment, or both. 4.Whole-body growth follows a sigmoid pattern •Timing of growth differs between males/females (particularly following puberty) •A lot of individual variability in growth 5.With advancing age, extrinsic factors contribute more to individual variability. 6.Extrinsic factors impact the organism differently at different times (developmental timing) 7.Although organisms may be deprived of growth leading to delays, these are not always long-term effects (catch-up growth)

•Individuals are especially sensitive during periods of rapid growth A.True B.False

A. True

•Maturity can be inferred through a combination of age and size together. A.True B.False

B. False Maturity cannot be inferred through age alone, size alone, or age and size together.

______________ is an increase in the absolute number of cells during the fetal period. A.Structural growth B.Hyperplasia C.Hypertrophy D.Embryonic growth

B. Hyperplasia

•______________ is an increase in the relative sizes of individual cells. A.Structural growth B.Hyperplasia C.Hypertrophy D.Embryonic growth

C. Hypertrophy

•The relation between increases in height and weight is... A.Increases in weight and height gain occur simultaneously B.Increases in weight gain precedes an increase in height gain C.Increases in height gain precedes an increase in weight gain D.These growth rates are unrelated

C. Increases in height gain precedes an increase in weight gain Peak weight velocity follows peak height velocity Males: Delay of 2.5-5 months Females: Delay of 3.5-10.5 monthes

Here are 2 graphs depicting growth curves of weight for males and females. The X axis shows age in years and the Y axis shows weight in kilograms. Both graphs show a sigmoid pattern with slightly different patterns for males and females. Females are slightly more variable in their weight trajectories following puberty, than males, although males weight more on average. Males are taller on average than females, so males weighing more on average makes sense.

Distance curves for weight

GENETIC CAUSES

Genetic disorders + dominant disorders = defective gene from one parent + recessive disorders = defective gene from each parent can also result from mutation of a gene effects on growth and maturation are variable + sometimes defective genes can produce no meaningful effects in the phenotype

Transcript: Let's do another spotlight on teratogens, by looking at exposure to cannabis during pregnancy. There are a number of positive uses for cannabis, such as decrease in nausea, weight gain, pain reduction, treatment of anxiety, and even slowing tumor growth. Factors like reduction in nausea, pain, or anxiety are particularly useful attributes for pregnant women.

However, the active component of cannabis, tetrahydrocannabinol or THC, can pass through the placental barrier and impact a fetus. Research on its effects on pregnancy in the general population is somewhat challenging, due to its illegality and difficulty in assessing dosage. However, research has shown some effects on children exposed to cannabis prenatally, including mild withdrawal symptoms following birth, differences in fetal growth trajectories, delays in some cognitive functions, emotional and behavioral consequences, as well as, higher use of tobacco or marijuana use later in life.

•Genetic, teratogenic, and other extrinsic factors all can affect prenatal development •Exposure and timing matter •Tissues undergoing rapid development at time of exposure are most vulnerable •How exposure occurs can change how the embryo/fetus is affected

In sum, genetic, teratogenic, and other extrinsic factors all can affect prenatal development, but... Exposure and timing matter in how or how much they affect the embryo or fetus.

VARIABILITY OF PHYSIOLOGICAL MATURATION A great case study of the variability of physiological maturation is the football player, Isaiah Stokes. In 8th grade, he was 6'7" and weighed 225 lbs.

In this picture Isaiah Stokes was in 8th grade and stood at 6' 7", 225 lbs

Adulthood and Aging: Weight •A lot of variability based on lifestyle, environment, health, etc. •Average adult starts gaining weight in the 20s. •Diet and exercise •Loss of muscle mass •Average adult starts losing weight after their 60's, due to normal aging.

Like during childhood, weight is variable in adulthood, due to extrinsic factors. Unfortunately, weight gain usually does not stop at puberty. The average adult starts gaining weight in their 20's. .... through changes in diet, exercise, and other activities. These changes in activities and other age-related factors lead to a loss of muscle mass. More so than in childhood, there is a lot of variability in weight based on food choices and activity level. For example, adults with an office job will be more sedentary, than an adult who performs manual labor in his or her job. Later in life, weight begins to decline due to normal declines in aging, such as a decrease in height, loss of muscle mass, loss of health, and less autonomy in daily activities as caregivers assist with food preparation and other activities.

•What substances, environments or situations are pregnant women encouraged to avoid? • •What substances, environments or situations are women encouraged to take during pregnancy?

Pregnant women are encouraged to avoid certain prescription or illicit drugs, smoking tobacco, or alcohol. They're also encouraged to avoid activities involving harsh chemicals, like painting, or changing their cat's litter box, as it can put them at greater risk for toxoplasmosis. They're encouraged to reduce their raw food, unpasteurized, high mercury, or undercooked food intake, like sushi or tuna. And they are encouraged to avoid some types of exercise, including ones where they're likely to fall as in volleyball or horseback riding Pregnant women are encouraged to drink water and consume healthy foods, especially ones rich in folic acid. Research has shown that folic acid will reduce the incidence of midline defects in fetuses, like spina bifida. They are also encouraged to do low impact exercise, like walking, swimming, or yoga, to maintain fitness and relieve stress.

Relative Growth •Different parts of the body have different rates of growth •Thought experiment: According to this graph, which body part(s) grow more slowly/quickly?

Relative growth is when different parts of the body have different rates of growth. The graph below shows how body proportions change at different stages of a human's life. According to this image, which body part(s) grow more slowly or quickly? According to this graph, the body proportions change from head-heavy and shorter limbs near birth to more adult proportions. The head grows at a relatively slow rate, while the trunk and limbs growth at a more rapid rate. Now, think critically. How might males and females differ in their relative growth rate, during adolescence?

FETAL NOURISHMENT

Role of the placenta? + allow transfer of oxygen, nutrients, waste What else does the placental barrier do? + prevents mixing of blood of mother and baby Poor maternal health status can affect fetus Fetal nourishment is the extrinsic factor with the most influence on fetal development

Sex affects the timing and extent of growth. Females tend to mature more quickly than males do in a variety of domains. For example, the mean age of adolescent growth spurt is 9 years in females and 11 years in males.

SEX Affects timing and extent of growth On average, females tend to mature faster than boys In a variety of domains - motor, cognitively, growth, etc. •Mean age at adolescent growth spurt: females (9 yrs) and males (11 yrs) •Although keep in mind these are *averages*

•Tanner stages •"an objective classification system that providers use to document and track the development and sequence of secondary sex characteristics of children during puberty" (pg 1, Emmanuel & Bokor, 2019)

The Tanner stages are an objective classification system that clinicians and researchers use to document and track a child's transition through puberty, by marking secondary characteristics.

SPOTLIGHT: GENETIC CAUSES

Trisomy 21 (down syndrome) genetic disorder caused by when abnormal cell division results in an extra full or partial copy of chromosome 21 symptoms/effects: + mild-moderate intelligence deficits + physical growth delays + unique facial characteristics + motor delays

The typical pattern of development is that individuals grow up, then out. This relation is demonstrated in the graphs of the right. The top graph is weight gain, and the bottom graph is height gain. The X axes for both graphs are age in year and the Y axes are kilograms per year for the top graph, and height gain by year in the bottom graph. There is a delay between peak height velocity and peak weight velocity.

Velocity curves for weight •Individuals grow up, then fill out • •Peak weight velocity follows peak height velocity •Males: delay of 2.5-5 months •Females: delay of 3.5-10.5 months

2. FETAL DEVELOPMENT

additional growth and cell differentiation of the fetus, plus functional capacities growth occurs in 2 ways: + hyperplasia - an increase in the absolute number of cells + hypertrophy - increases the relative sizes of individual cells the direction of growth occurs in 2 ways: + cephalocaudal - head/facial structures > upper body > lower body + proximodistal - trunk tends to advance> nearest parts of the limbs > distal parts of limbs + plasticity - the capability to take on a new function (i.e., although differentiation occurs during growth to perform a specialized function, some cells are still plastic)

TERATOGENS

any drug or chemical agent that causes abnormal prenatal development upon exposure + teratogens delivered through nourishment system act as malformation-producing agents Placenta screens some substances (e.g., large viruses) but not all harmful ones * Exposure to cannabis during pregnancy + medical uses: decreases nausea, weight gain, reduces pain/spasticity/inflammation, slows tumor growth, reduces anxiety + the active component of cannabis, tetrahydrocannabinol (THC) can pass through the placental barrier symptoms/effects in fetus and later development: +mild withdrawal symptoms at birth +fetal growth trajectories +delays decreases academic achievement and impaired problem-solving, memory, planning, impulsivity, and attention +emotional and behavioral consequences +higher incidence of early tobacco and marijuana use in child

1. EMBRYONIC GROWTH

increasing # of cells cell differentiation occurs -process wherein cells become specialized, forming specific tissues and organs -limbs are formed at 4 weeks -human "form" becomes noticeable at 8 weeks

PRENATAL DEVELOPMENT

the process in which a baby develops from a single cell after conception into an embryo and later a fetus. 2 phases -embryonic growth (conception-8 weeks) -fetal development (9 weeks- birth)

EXTRINSIC FACTORS

•"Extrinsic" factors include anything resulting from external forces •Extrinsic factors can affect fetus through nourishment or physical environment •Examples: traumatic injury, environmental temperature, x-rays or gamma rays, changes in atmospheric pressure, environmental pollutants, extreme internal environmental temperature (i.e., fever or hypothermia), maternal obesity, gestational diabetes, viral infections, etc. Transcript: Extrinsic factors include anything resulting from external forces. This can be through nourishment or the physical environment.... This category is very broad, including exposure to radiation, X-rays, or gamma rays. If the mother was in a car crash, fell, or was physically assaulted. Or even health conditions, like maternal obesity, gestational diabetes, or certain illnesses.

POSTNATAL DEVELOPMENT Following growth, we keep growing, but it isn't a consistent rate of growth. Most patterns of growth from early childhood through adulthood follows a sigmoid pattern. A sigmoid pattern is a growth curve with multiple phases of growth. There's an initial period of slow growth, called a lag phase. Then, a rapid period of growth, called the exponential phase... ...followed by a stationary or deceleration phase, one marked by little growth

•After birth, guess what? We keep growing. •We do not always exhibit consistent rates of growth •Overall growth, height, weight, relative growth, etc. follow a sigmoid curve •Growth curve which includes multiple phases of growth •Lag phase à exponential/log phase à stationary phase

Weight! Now, let's talk about the growth rate of weight. Weight also follows a sigmoid pattern, ...but unlike height, weight is VERY susceptible to extrinsic factors. I think you can guess why... because weight is closely tied to food intake, nutrition, activity level, and home environment.

•Also a sigmoid pattern (see a theme?) •VERY susceptible to extrinsic factors •Can you guess why? •Weight closely tied to food intake, nutrition, activity level, and home environment •Nutrition/feeding: Children at greatest risk for higher weight or obesity consumed more fat in their diet in their 2nd year of life (Karaolis-Danckert et al., 2007) •Parental factors: The highest BMIs were observed in children (7-10 years) with the highest amount of family risk factors, such as high maternal BMI and lower levels of education (Valerio et al., 2006)

Relative Growth Differences in growth rate in adolescent males and females are affected by the qualitative changes brought on by puberty. Males grow taller with broader shoulders. Females tend to grow broader hips and breasts.

•Body proportions change from head-heavy, short-legged form at birth to adult proportions • •Thought experiment: In adolescence, how might males/females differ in their relative growth rate?

Extrinsic Factors on Postnatal Growth Even though some researchers believe that physiological maturation proceeds due to innate or intrinsic factors, there is an acknowledgement that extrinsic factors affect postnatal growth. For example, catch-up or compensatory growth is when faster than typical growth patterns compensate for a period of growth inhibition. So, Children who are malnourished for a period of time tend to weigh less and have a shorter stature, than peers. Then is given adequate nutrition and intervention, the malnourished children may experience an increased rate of weight and height gain following the period of malnutrition and catch-up to their peers. Catch-up growth demonstrates that extrinsic factors influence physiological growth and that intrinsic factors are not solely responsible. Like during prenatal growth, the timing, duration, and severity of the negative influence determines ... how affected the trajectory is... How much catch-up growth will occur... And whether catch-up growth can compensate for the negative influence. The timing of the negative influence can affect the severity of the effect or if children can compensate for the damage. Individuals are especially sensitive to negative influences during periods of rapid growth.

•Catch-up growth (or, compensatory growth/gain) •Faster than typical growth patterns which compensates for a transient period of growth inhibition (Wit & Boersma, 2002) •Catch-up growth demonstrates extrinsic influences •Timing, duration, and severity of the negative influence determines its effect on the trajectory. •How affected the trajectory is •How much catch-up growth occurs •Whether catch-up growth can compensate for the negative influence •Individuals are especially sensitive during periods of rapid growth

Secondary sex characteristics appear as a function of maturation... Remember! Maturation is the qualitative advance in biological make-up. Puberty is a perfect example of maturation, as children pre- and post-puberty are very different in their physical appearance and biological functioning qualitatively. Secondary sex characteristics co-occur with age, but they're not dependent on an individual's age. Different rates of growth of secondary sex characteristics occur at different rates across and within children. A standard method of rating a child's progress through puberty is using Tanner staging.

•Characteristics appear as a function of maturation (qualitative advance in biological make-up) •Age-related, but certainly not bound. •Characteristics can appear earlier / later in early / late maturing children •Variations among preteens may be easily observed in the appearance of some secondary sex characteristics •Tanner Stages (see next slide) •Qualitative sequence of typical change in puberty

However, physiological maturation does not progress universally and is not necessarily predicted by age. Children vary in their rate of physiological maturation, a la variability in development. Two children of the same age can have different maturation status or sizes, thus it is difficult to infer maturity from age alone, size alone, or age and size together.

•Children vary in physiological maturation rate •Paradox: "Variability" in development •Two children of the same age can have different a different maturation status. •Maturity cannot be inferred through age alone, size alone, or age and size together.

It should be noted that most of the children sampled in these studies were eventually adopted or adopted very early in life. Children, who remained in these orphanages into toddlerhood, had disrupted growth rates and more severe impairments later in life. Children who were removed before 6 months of age had significantly less profound cognitive and language delays. If you frame this finding into what we understand about growth and developmental timing, children who were deprived in the orphanages for longer, experienced deprivation during the sensitive periods for sensory, motor and language, and in some cases higher cognition

•Children who were removed from institutions at earlier ages (e.g., before 6 months) had less profound cognitive and language delays, than children removed as toddlers or older.

Physiological Maturation Physiological maturation is considered to be a developmental process leading to a state of full functioning. If you remember the maturational theory of development, it has this idea that physical or biological processes are controlled by innate factors. Therefore, the organism will reach an "end state" of adulthood with the passage of time. As children and youth become older, they increase in size and mature into adulthood in a relatively consistent or predictable, a la universality of development. Therefore, age, growth in body size, and physiological maturation are related to one another.

•Developmental process leading to a state of full functioning •Maturational theory -> controlled innate factors •As children and youth become older, they grow in size and mature •Paradox: "Universality" of development •Age, growth in body size and physiological maturation are related to one another

Height! Height follows a sigmoid pattern of growth. Both sexes have similar trajectories, but there is different timing between the sex. I've copied the descriptions of growth rates in height between the sexes, but let's look at graph of them.

•Follows a sigmoid pattern •Multiple changes of rate of growth (exponential, linear, and asymptotic rates) •Similar trajectories, but different timing between sexes •Females •Adolescent growth spurt typically begins at age 9 •Peak height velocity occurs at 11.5 to 12 years •Growth in height tapers off around 14, ends around 16 •Males •Adolescent growth spurt typically begins at age 11 •Peak height velocity occurs at 13.5 to 14 years •Growth in height tapers off around 17, ends around 18

Adulthood and Aging After the rate of growth flattens after puberty, height is largely stable across adulthood. Height slightly declines as a result of normal aging or disease.

•Height is a (largely) stable trait in adulthood but may decrease in older adulthood •Osteoporosis, compression of cartilage pads, etc.

Let's reflect on that last point: Individuals are especially sensitive during periods of rapid growth. A negative influence early in development, as denoted by the red shape, will impact later development less, because it wasn't during an important time for sensory, motor, language, or higher cognition. However, if it happens at a sensitive period or peak rate of growth, OR, if the influence lasts for a longer duration of time in development, the negative influence can have more devastating effects on development. This concept is why having basic knowledge of abilities, sensitive periods, growth, and developmental timing are so important to our understanding of development or intervention across the lifespan. The timing and mechanisms of change tell us how development occurs and how to shape it.

•Individuals are especially sensitive during periods of rapid growth

A lot of research has been done on this population of children, but I tried to distill it into bite-sized chunks for this course. Overall, children exhibited impairment in their language, cognitive, and physical development. Children who were institutionalized had shorter heights, weights, and smaller head circumference, than non-institutionalized Romanian children. In turn, institutionalized children developed delays in motor abilities and worsening of existing motor delays or disorders. Think about what we know about growth during the early part of life....

•Language, cognitive, and physical impairments (Kaler & Freeman, 1994; Rutter et al., 2007; Rutter & ERA study team, 1998) •Negative correlation between institution rearing and developmental progress at initial adoption (table on the right) •Institutionalized children had shorter height, weight, and head circumference, than non-institutionalized children; however, height and weight were approximately or close to typical estimates by 6 years of age. •Some motor delays or worsening of delays in children with motor disorders, overall delays in language and cognitive functioning

BUT... children did not always maintain these differences in developmental trajectories .... Researchers observed catch-up growth. For example, post-institutionalization, most children were close to normal in physical characteristics and the negative correlation between institutionalization and developmental progress disappeared...although delays are still common in this population.

•Language, cognitive, and physical impairments (Kaler & Freeman, 1994; Rutter et al., 2007; Rutter & ERA study team, 1998) •Negative correlation between institution rearing and developmental progress at initial adoption (table on the right) •Institutionalized children had shorter height, weight, and head circumference, than non-institutionalized children; however, height and weight were approximately or close to typical estimates by 6 years of age. •Some motor delays or worsening of delays in children with motor disorders, overall delays in language and cognitive functioning •Catch-up growth (Wickett et al., 2000) •By 6 years of age post-institutionalized, most adopted children had approximately normal physical characteristics (height, weight, head circumference, etc.: Wickett et al., 2000). •Correlation between institutional rearing and development progress disappeared at 4 years (table on the right) •Delays were still common, but less severe later in life

(other) extrinsic factors Transcript: Let's do a spotlight on a very common extrinsic factor, maternal diabetes. A mother can already have diabetes, or develop gestational diabetes after pregnancy. Maternal diabetes can cause chronic, mild hypoxia and intrauterine growth restriction for the fetus, especially if the diabetes is untreated. Effects can result in a lower IQ of the child, delays in psychomotor development, impaired glucose homeostasis, and insulin resistance

•Maternal diabetes •Gestational or pre-existing •Can cause chronic hypoxia and intrauterine growth restriction for the fetus •Effects on fetus: lower IQ of child, elevated risk of abnormal glucose homeostasis and insulin resistance, delays in psychomotor development

A Natural experiment of Early Deprivation and Developmental Timing Before ending this lecture, I am going to familiarize you with a natural experiment of early deprivation and developmental timing. Due to a population crisis, Romania's government instituted bans on family planning in the 1960's through the 90's. They encouraged parents unable to care for their children to leave them at state-run orphanages. Unfortunately, these orphanages had extremely poor living conditions for the children. There was poor hygiene, few caregivers, little environmental enrichment, high rates of abuse, and little opportunity for movement or activity. Think about what you now know about growth rates. How could these conditions affect development in childhood?

•Romanian orphanages (~1960's through 1990's) •Huge influx in children to orphanages in Romania, due to political climate •Extremely poor living conditions: few caregivers, poor nutrition/hygiene/care, little environmental enrichment, limited movement in facilities, high rates of abuse •How might conditions affect a child's rate of growth? How would these conditions affect their motor and physical development?

POSTNATAL DEVELOPMENT The timing of growth periods depend on individuals and groups... ... in particular growth differs for the sexes. When I talk about sex in this lecture or this class, I am only speaking to a male versus female comparison, since most of the literature is based upon this binary classification. However, sex could change patterns of growth for people outside of these binary classifications, such as transgender or gender non-conforming individuals. Please keep this mind, as you evaluate any of the sections on sex differences.

•Timing of spurts and steady periods can vary between individuals and groups •Timing differs between the sexes

Exposure and Timing Matters A lot of factors influencing prenatal development depend on exposure and timing. Tissues undergoing rapid development are most vulnerable to effects of teratogens, than after tissues have been established. And, the way in which exposure occurs can change how the fetus is affected. Binge-drinking alcohol during pregnancy is associated with greater downstream effects, than mild or occasional drinking.

•Tissues undergoing rapid development at time of exposure are most vulnerable •Also the way in which exposure occurs can change how the fetus is affected •E.g., binge-drinking alcohol during pregnancy is typically associated with greater downstream effects, than occasional or mild drinking