Child Growth and
Development
Dr. Andrew Whitehead
More Information at:
Biological Beginnings
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Genetic Foundations of Child
Development
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Structure and Function of Genes
 Genes-
the basic unit of heredity
 46 Chromosomes, 23 distinct pairs – one pair from
mother and one pair from father
 DNA
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Formation of Reproductive Cells
– male and female reproductive cells
 Sperm in male – Ova in female
 Gametes
Genetic Basis
of Individual Traits
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Common mechanisms of genetic transmission
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Alleles - genes located at the same point on corresponding
(paired) chromosomes and provide instructions for a particular
physical characteristic
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Dominant gene – overriding gene that determines the
characteristic (dark features, e.g., dark hair/ brown eyes)
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Recessive gene – influencing gene, primarily when an identical
gene is contained in the allele pair (light features, e.g. blonde
hair/ blue eyes)
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Codominance – when both genes of the allele pair, although not
identical, share the influence on a physical characteristic
Problems in Genetic Instruction
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Genetic disorders result in major physical problems and/or mental
retardation
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Chromosome abnormalities – uneven division of chromosomes during
meiosis
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1 in 150 births may result in:
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An extra chromosome
A missing chromosome
A wrongly formed chromosome
Single-gene defects - inherited from one or both parents
Common chromosomal and genetic disorders include (see Table 3-1):
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Down Syndrome – extra 21st chromosome
Klinefelter Syndrome – boys only; XXY
Turner Syndrome – girls only; X chromosome, missing second
Hungington Disease (HD)
Phenylketonuria (PKU)
Sickle Cell Disease
Cystic Fibrosis (CF)
The Awakening of Genes
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Some genes are inactive and influence
development later during maturation
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Canalization – tight genetic control of a certain
development aspect
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Not canalized – most acquired skills
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Basic motor skills, e.g., crawling, sitting, walking
Reading, writing, math, social skills
Sensitive periods are critical in physical
development, perceptual ability, brain
development, and language acquisition
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Toxic substances are particularly dangerous during
prenatal development of limbs, organs, facial
structures, and brain connections
The Blending of Heredity and
Environment
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Genetics are greatly influenced by environmental and personal factors:
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Nutrition
Illness
Medication
Stressful events
Intensity of stimulation
Opportunities for physical activity
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Personality and Intellect are the outcomes of both nature and nurture effects
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Genetics affect a child’s response to the environment
through three mechanisms:
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Passive gene-environment relation – parents genetic tendencies correlate to the
context in which they raise their children
Evocative gene-environment relation – a child’s own characteristic elicits specific
responses form the environment around them
Active gene-environment relation - a child’s talent influences the environment
Acknowledging Nature and Nurture
in Children’s Lives
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Value individual differences among children and
adolescents
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The environment (along with genetics) influences every
aspect of development
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Intervene when children display intellectual, social, and
emotional struggles
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Encourage children to select activities that promote
growth and development
Period of the Embryo (week 2 - 8)
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Major body structures and life support are formed
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Placenta grows - forms umbilical cord
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Provides food, liquid, oxygen
Removes waste
Secretes hormones to sustain embryonic growth
Embryo develops
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Head and heart
From top to bottom (head first, feet last)
From inside to outside (torso before limbs, arms and legs before
hands and feet)
Neural tube (eventual brain and spinal cord) forms
Internal organs appear
Buds and limbs develop
Fingers and toes are recognizable at 8 weeks
Period of the Fetus (week 9 to birth)
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Grows in size and weight, sensory abilities, brain
structures and organs needed for survival
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Third month
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Four month
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Skin is red and wrinkled; body is lean; fingernails are evident
Development of respiratory and central nervous system continues
Seventh month (avg. weight 2 lb. 14 oz.)
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Rapid growth in length (height) continues
Fine hair growth covers body
Movement is felt by mother
Sixth month (avg. weight 1 lb. 13 oz.)
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Rapid growth in length (height)
Slow weight increase
Hair growth on head and eyebrows
Fifth month
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Head is large, slows growth
Eyes move into place; increasingly human-looking
Genitalia form
Reflex and muscular movement (although not felt)
Eyes open; eyelashes and toenails form
Body fills out
Eighth month (avg. weight 4 lb. 10 oz.)
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Skin becomes pink and smooth; fat growths beneath skin
Testes descend (in males)
Medical Care
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Preparing for pregnancy (starts before
conception)
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Other factors
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Watch diet
Take approved vitamin supplements
Exercise
Avoid alcohol and drugs (includes OTC meds)
Hypertension or diabetes
Under age 17 = low birth weight
Mothers over 35 and fathers over 40 = higher risk for
genetic problems
Seek a genetic counselor
Avoiding Harmful Substances
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Teratogens – potentially harmful substance that can
cause problems during prenatal development
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Prescription or non-prescription drugs or
Infectious agents, e.g., rubella, syphilis, HIV
Environmental chemicals, e.g., lead or polychlorinated biphenyls
Alcohol causes FAS - (Fetal Alcohol Syndrome) delayed
physical and motor development, facial abnormalities, mental
retardation, impulsivity and other behavior problems, learning
disabilities or minor physical problems
Nicotine - low birth weight and occasionally miscarriage
Drugs – various problems
HIV and AIDS – Delayed motor skills, language, and cognitive
development; major health risks and problems
Maternal anxiety also contributes to low birth weight,
irritability, and problems with attention and dealing with
negative emotional issues
Sensitive Periods in Prenatal
Development
Examples of Risk Factors for
Healthy Neurological Development
Implementing Medical Procedures
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Ultrasonography – detects age, major abnormalities,
and number/gender of fetuses
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CVS (Chorionic Villus Sampling) for high risk
pregnancies
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Invasive procedure performed at 7-12 weeks
Needle inserted into abdomen or tube guided through cervix to
collect chorionic villi (blood vessels)
Used to detect chromosomal abnormalities
May damage embryo/fetus arm or leg; cause miscarriage (rare)
Amniocentesis –
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Needle inserted into abdomen; fluid drawn from uterus
Fetal protein and cells analyzed for neural tube defects or
chromosomal abnormalities
May cause fetal trauma, infection, or miscarriage
Supporting Parents,
Protecting Babies
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Encourage women to evaluate their health before
pregnancy
Remind sexually active women also to be health
conscious
Encourage new mothers to seek medical care
Remind expectant mothers to avoid teratogens
Encourage them to relax and speak their minds
Talk to fathers about their experiences and feelings
Advise parents about appropriate care when children
have been exposed to teratogens
Intervene when mothers continue substance abuse after
birth
Birth of the Baby
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Preparation for Birth
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Child birth classes provide:
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Relaxation and breathing techniques for focus, pain
management, reduction of fear, effective use of muscles
during birth
Support from a birth coach (spouse, partner, friend, family)
Basic education about physiology and mechanics of delivery,
positions, pain options, and medical interventions
Support for decisions about where and when birth may occur
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Hospitals
Community birth centers
Home settings
The Birth Process
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Typically at 38 - 40 weeks, both a mother’s hormonal
changes and the maturation of the fetus trigger birth
Braxton Hicks contractions exercise the uterine muscles
without opening the cervix
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95% head-downward position
Cesarean delivery may result:
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Breech position – butt or legs first
Sideways position – shoulder first
Several days before labor, the mother experiences
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Decent of baby into pelvis
Rush of energy
Weight loss of 1 to 4 pounds from hormonal changes
Vaginal secretions
Difficulty sleeping
The Birth Process (cont’d)
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First stage of labor
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Second stage of labor
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Regular contractions and widening of cervix to 10 cm (4”) dilat.
Pelvis and back pain
First time mothers 12 - 16 hours;
6 - 8 hours for second birth or more
Contractions become stronger and longer
Cervix is fully dilated, baby proceeds down birth canal
Baby is born
This process may last ½ to 2 hours (first baby)
Third stage of labor
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Afterbirth expelled by uterus (placenta and fetal membranes)
Usually baby is alert, looking around the room
Complications and Interventions
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Midwives, coaches, and medical staff may relieve pain without using meds
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Warm whirlpool
Massage
Music
Hypnosis
Biofeedback
Visual images of the cervix opening
Physicians may use meds and interventions, e.g.,
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Analgesics
Epidural analgesia (spinal injection)
Anesthetics
Opioids (a.k.a. narcotics)
Induced labor using Pitocin
Cesarean delivery (30%)
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Fetal distress
Mother’s health problems
Failure for labor to progress
Birth canal infections
Presence of multiple babies
Babies at Risk
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Premature infant – babies are considered premature if born before
the end of week 37
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Premature labor is triggered by
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Seriously premature babies suffer from
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Infection, multiple gestations (twins or triplets), fetus abnormalities,
death of fetus, uterine or cervical abnormalities, serious disease in
mother
Breathing problems, anemia, brain hemorrhages, feeding problems,
instability in temperature
Babies born small for date are at risk for
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Neurological deficiencies, structural problems with body parts, difficulty
with breathing and vision
Low birth size and weight after sufficient time in the uterus is often
caused by exposure to teratogens or chromosomal abnormalities
Developmental Care for
Babies at Risk
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Fragile infants need
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Medical staff to
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Reduce their exposure to noise and light
Regulate the amount of handling
Position them in a way that increases circulation
Parents to
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Stay actively involved during infant care
Stay informed of the infant’s needs
Arrange a proper activity schedule to ensure sleep and rest
Cuddle and carry them often and for long periods
Swaddle them in a blanket with arms bent allowing the baby’s
hands to reach their mouth for sucking
Massage them
Stay informed through early childhood development
Enhancing Caregivers’ Sensitivity
to Newborn Infants
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Talk about the baby’s sensations (physiological detection of
environmental stimuli) and perceptions (interpretation of sensations)
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Point out the newborn’s states of arousal (sleepiness and
wakefulness) and reflexes (automatic motor response to stimuli)
experienced throughout the day
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Encourage parents to become aware of their baby’s responses to
certain stimuli
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Suggest different types of soothing techniques, i.e., listening to a
clothes dryer, nursing, sleeping on father’s chest, riding in a car
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Model sensitivity to baby’s interaction preferences
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Teach parents how to perform care-taking functions, e.g., feeding,
bathing, diaper changing, and proper carrying or holding
Offer continued support for parents of fragile infants
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