Child Growth and Child Growth and DevelopmentDevelopment

Dr. Andrew WhiteheadDr. Andrew WhiteheadMore Information at:More Information at:

Biological Beginnings Biological Beginnings Genetic Foundations of Child Genetic Foundations of Child

DevelopmentDevelopmentStructure and Function of GenesStructure and Function of Genes

Genes- the basic unit of heredityGenes- the basic unit of heredity46 Chromosomes, 23 distinct pairs – one pair from 46 Chromosomes, 23 distinct pairs – one pair from

mother and one pair from fathermother and one pair from fatherDNA DNA

Formation of Reproductive CellsFormation of Reproductive CellsGametes – male and female reproductive cellsGametes – male and female reproductive cellsSperm in male – Ova in femaleSperm in male – Ova in female

Genetic Basis Genetic Basis of Individual Traitsof Individual Traits

Common mechanisms of genetic transmissionCommon mechanisms of genetic transmission Alleles Alleles - genes located at the same point on corresponding - genes located at the same point on corresponding

(paired) chromosomes and provide instructions for a particular (paired) chromosomes and provide instructions for a particular physical characteristicphysical characteristic

Dominant geneDominant gene – overriding gene that determines the – overriding gene that determines the characteristic (dark features, e.g., dark hair/ brown eyes)characteristic (dark features, e.g., dark hair/ brown eyes)

Recessive geneRecessive gene – influencing gene, primarily when an identical – influencing gene, primarily when an identical gene is contained in the allele pair (light features, e.g. blonde gene is contained in the allele pair (light features, e.g. blonde hair/ blue eyes)hair/ blue eyes)

CodominanceCodominance – when both genes of the allele pair, although – when both genes of the allele pair, although not identical, share the influence on a physical characteristicnot identical, share the influence on a physical characteristic

Problems in Genetic InstructionProblems in Genetic Instruction Genetic disorders result in major physical problems and/or mental Genetic disorders result in major physical problems and/or mental

retardationretardation Chromosome abnormalitiesChromosome abnormalities – uneven division of chromosomes during – uneven division of chromosomes during

meiosismeiosis 1 in 150 births may result in:1 in 150 births may result in:

An extra chromosomeAn extra chromosome A missing chromosomeA missing chromosome A wrongly formed chromosome A wrongly formed chromosome

Single-gene defectsSingle-gene defects - inherited from one or both parents - inherited from one or both parents

Common chromosomal and genetic disorders include Common chromosomal and genetic disorders include (see Table 3-1):(see Table 3-1): Down Syndrome – extra 21Down Syndrome – extra 21stst chromosome chromosome Klinefelter Syndrome – boys only; XXYKlinefelter Syndrome – boys only; XXY Turner Syndrome – girls only; X chromosome, missing second Turner Syndrome – girls only; X chromosome, missing second Hungington Disease (HD)Hungington Disease (HD) Phenylketonuria (PKU)Phenylketonuria (PKU) Sickle Cell DiseaseSickle Cell Disease Cystic Fibrosis (CF)Cystic Fibrosis (CF)

The Awakening of GenesThe Awakening of Genes Some genes are inactive and influence Some genes are inactive and influence

development later during maturationdevelopment later during maturation CanalizationCanalization – tight genetic control of a certain – tight genetic control of a certain

development aspectdevelopment aspect Basic motor skills, e.g., crawling, sitting, walkingBasic motor skills, e.g., crawling, sitting, walking

Not canalized – most acquired skillsNot canalized – most acquired skills Reading, writing, math, social skillsReading, writing, math, social skills

Sensitive periodsSensitive periods are critical in physical are critical in physical development, perceptual ability, brain development, perceptual ability, brain development, and language acquisitiondevelopment, and language acquisition Toxic substances are particularly dangerous during Toxic substances are particularly dangerous during

prenatal development of limbs, organs, facial prenatal development of limbs, organs, facial structures, and brain connectionsstructures, and brain connections

The Blending of Heredity and The Blending of Heredity and EnvironmentEnvironment

Genetics are greatly influenced by environmental and personal factors:Genetics are greatly influenced by environmental and personal factors: NutritionNutrition IllnessIllness MedicationMedication Stressful eventsStressful events Intensity of stimulationIntensity of stimulation Opportunities for physical activityOpportunities for physical activity

Personality and Intellect are the outcomes of both nature and nurture effectsPersonality and Intellect are the outcomes of both nature and nurture effects

Genetics affect a child’s response to the environment Genetics affect a child’s response to the environment through three mechanisms:through three mechanisms: Passive gene-environment relation – parents genetic tendencies correlate to the Passive gene-environment relation – parents genetic tendencies correlate to the

context in which they raise their childrencontext in which they raise their children Evocative gene-environment relation – a child’s own characteristic elicits specific Evocative gene-environment relation – a child’s own characteristic elicits specific

responses form the environment around themresponses form the environment around them Active gene-environment relation - a child’s talent influences the environmentActive gene-environment relation - a child’s talent influences the environment

Acknowledging Nature and Nurture Acknowledging Nature and Nurture in Children’s Livesin Children’s Lives

Value individual differences among children and Value individual differences among children and adolescentsadolescents

The environment (along with genetics) influences every The environment (along with genetics) influences every aspect of developmentaspect of development

Intervene when children display intellectual, social, and Intervene when children display intellectual, social, and emotional strugglesemotional struggles

Encourage children to select activities that promote Encourage children to select activities that promote growth and developmentgrowth and development

Period of the Embryo Period of the Embryo (week 2 - 8)(week 2 - 8) Major body structures and life support are formedMajor body structures and life support are formed

Placenta grows - forms umbilical cordPlacenta grows - forms umbilical cord Provides food, liquid, oxygenProvides food, liquid, oxygen Removes wasteRemoves waste Secretes hormones to sustain embryonic growthSecretes hormones to sustain embryonic growth

Embryo develops Embryo develops Head and heartHead and heart From top to bottom (head first, feet last)From top to bottom (head first, feet last) From inside to outside (torso before limbs, arms and legs before From inside to outside (torso before limbs, arms and legs before

hands and feet)hands and feet) Neural tube (eventual brain and spinal cord) formsNeural tube (eventual brain and spinal cord) forms Internal organs appearInternal organs appear Buds and limbs developBuds and limbs develop Fingers and toes are recognizable at 8 weeksFingers and toes are recognizable at 8 weeks

Period of the FetusPeriod of the Fetus (week 9 to birth) (week 9 to birth) Grows in size and weight, sensory abilities, brain Grows in size and weight, sensory abilities, brain

structures and organs needed for survivalstructures and organs needed for survival Third monthThird month

Head is large, slows growthHead is large, slows growth Eyes move into place; increasingly human-lookingEyes move into place; increasingly human-looking Genitalia formGenitalia form Reflex and muscular movement (although not felt)Reflex and muscular movement (although not felt)

Four monthFour month Rapid growth in length (height)Rapid growth in length (height) Slow weight increaseSlow weight increase Hair growth on head and eyebrowsHair growth on head and eyebrows

Fifth monthFifth month Rapid growth in length (height) continuesRapid growth in length (height) continues Fine hair growth covers bodyFine hair growth covers body Movement is felt by motherMovement is felt by mother

Sixth month (avg. weight 1 lb. 13 oz.)Sixth month (avg. weight 1 lb. 13 oz.) Skin is red and wrinkled; body is lean; fingernails are evidentSkin is red and wrinkled; body is lean; fingernails are evident Development of respiratory and central nervous system continuesDevelopment of respiratory and central nervous system continues

Seventh month (avg. weight 2 lb. 14 oz.)Seventh month (avg. weight 2 lb. 14 oz.) Eyes open; eyelashes and toenails formEyes open; eyelashes and toenails form Body fills outBody fills out

Eighth month (avg. weight 4 lb. 10 oz.)Eighth month (avg. weight 4 lb. 10 oz.) Skin becomes pink and smooth; fat growths beneath skinSkin becomes pink and smooth; fat growths beneath skin Testes descend (in males)Testes descend (in males)

Medical CareMedical Care Preparing for pregnancy (starts before Preparing for pregnancy (starts before

conception)conception) Watch dietWatch diet Take approved vitamin supplementsTake approved vitamin supplements ExerciseExercise Avoid alcohol and drugs (includes OTC meds)Avoid alcohol and drugs (includes OTC meds)

Other factorsOther factors Hypertension or diabetesHypertension or diabetes Under age 17 = low birth weightUnder age 17 = low birth weight Mothers over 35 and fathers over 40 = higher risk for Mothers over 35 and fathers over 40 = higher risk for

genetic problemsgenetic problems Seek a genetic counselorSeek a genetic counselor

Avoiding Harmful SubstancesAvoiding Harmful Substances TeratogensTeratogens – potentially harmful substance that can – potentially harmful substance that can

cause problems during prenatal developmentcause problems during prenatal development Prescription or non-prescription drugs orPrescription or non-prescription drugs or Infectious agents, e.g., rubella, syphilis, HIVInfectious agents, e.g., rubella, syphilis, HIV Environmental chemicals, e.g., lead or polychlorinated biphenylsEnvironmental chemicals, e.g., lead or polychlorinated biphenyls Alcohol causes FAS - (Fetal Alcohol Syndrome) delayed physical Alcohol causes FAS - (Fetal Alcohol Syndrome) delayed physical

and motor development, facial abnormalities, mental retardation, and motor development, facial abnormalities, mental retardation, impulsivity and other behavior problems, learning disabilities or impulsivity and other behavior problems, learning disabilities or minor physical problems minor physical problems

Nicotine - low birth weight and occasionally miscarriageNicotine - low birth weight and occasionally miscarriage Drugs – various problemsDrugs – various problems HIV and AIDS – Delayed motor skills, language, and cognitive HIV and AIDS – Delayed motor skills, language, and cognitive

development; major health risks and problemsdevelopment; major health risks and problems

Maternal anxiety also contributes to low birth weight, Maternal anxiety also contributes to low birth weight, irritability, and problems with attention and dealing with irritability, and problems with attention and dealing with negative emotional issuesnegative emotional issues

Sensitive Periods in Prenatal Sensitive Periods in Prenatal DevelopmentDevelopment

Examples of Risk Factors for Examples of Risk Factors for Healthy Neurological DevelopmentHealthy Neurological Development

Implementing Medical ProceduresImplementing Medical Procedures UltrasonographyUltrasonography – detects age, major abnormalities, – detects age, major abnormalities,

and number/gender of fetusesand number/gender of fetuses CVSCVS (Chorionic Villus Sampling) for high risk (Chorionic Villus Sampling) for high risk

pregnanciespregnancies Invasive procedure performed at 7-12 weeksInvasive procedure performed at 7-12 weeks Needle inserted into abdomen or tube guided through cervix to Needle inserted into abdomen or tube guided through cervix to

collect chorionic villi (blood vessels)collect chorionic villi (blood vessels) Used to detect chromosomal abnormalitiesUsed to detect chromosomal abnormalities May damage embryo/fetus arm or leg; cause miscarriage (rare)May damage embryo/fetus arm or leg; cause miscarriage (rare)

AmniocentesisAmniocentesis – – Needle inserted into abdomen; fluid drawn from uterusNeedle inserted into abdomen; fluid drawn from uterus Fetal protein and cells analyzed for neural tube defects or Fetal protein and cells analyzed for neural tube defects or

chromosomal abnormalitieschromosomal abnormalities May cause fetal trauma, infection, or miscarriageMay cause fetal trauma, infection, or miscarriage

Supporting Parents, Supporting Parents, Protecting BabiesProtecting Babies

Encourage women to evaluate their health before Encourage women to evaluate their health before pregnancypregnancy

Remind sexually active women also to be health Remind sexually active women also to be health consciousconscious

Encourage new mothers to seek medical careEncourage new mothers to seek medical care Remind expectant mothers to avoid teratogensRemind expectant mothers to avoid teratogens Encourage them to relax and speak their mindsEncourage them to relax and speak their minds Talk to fathers about their experiences and feelingsTalk to fathers about their experiences and feelings Advise parents about appropriate care when children Advise parents about appropriate care when children

have been exposed to teratogenshave been exposed to teratogens Intervene when mothers continue substance abuse after Intervene when mothers continue substance abuse after

birthbirth

Birth of the BabyBirth of the Baby Preparation for BirthPreparation for Birth

Child birth classes provide:Child birth classes provide: Relaxation and breathing techniques for focus, pain Relaxation and breathing techniques for focus, pain

management, reduction of fear, effective use of muscles management, reduction of fear, effective use of muscles during birthduring birth

Support from a birth coach (spouse, partner, friend, family)Support from a birth coach (spouse, partner, friend, family) Basic education about physiology and mechanics of delivery, Basic education about physiology and mechanics of delivery,

positions, pain options, and medical interventionspositions, pain options, and medical interventions Support for decisions about where and when birth may occurSupport for decisions about where and when birth may occur

HospitalsHospitals Community birth centersCommunity birth centers Home settingsHome settings

The Birth ProcessThe Birth Process Typically at 38 - 40 weeks, both a mother’s hormonal Typically at 38 - 40 weeks, both a mother’s hormonal

changes and the maturation of the fetus trigger birthchanges and the maturation of the fetus trigger birth Braxton Hicks contractions exercise the uterine muscles Braxton Hicks contractions exercise the uterine muscles

without opening the cervixwithout opening the cervix 95% head-downward position95% head-downward position Cesarean delivery may result: Cesarean delivery may result:

Breech position – butt or legs firstBreech position – butt or legs first Sideways position – shoulder firstSideways position – shoulder first

Several days before labor, the mother experiencesSeveral days before labor, the mother experiences Decent of baby into pelvisDecent of baby into pelvis Rush of energyRush of energy Weight loss of 1 to 4 pounds from hormonal changesWeight loss of 1 to 4 pounds from hormonal changes Vaginal secretionsVaginal secretions Difficulty sleepingDifficulty sleeping

The Birth Process (cont’d)The Birth Process (cont’d) First stage of laborFirst stage of labor

Regular contractions and widening of cervix to 10 cm (4”) dilat.Regular contractions and widening of cervix to 10 cm (4”) dilat. Pelvis and back painPelvis and back pain First time mothers 12 - 16 hours; First time mothers 12 - 16 hours;

6 - 8 hours for second birth or more6 - 8 hours for second birth or more Contractions become stronger and longerContractions become stronger and longer

Second stage of laborSecond stage of labor Cervix is fully dilated, baby proceeds down birth canalCervix is fully dilated, baby proceeds down birth canal Baby is bornBaby is born This process may last ½ to 2 hours (first baby)This process may last ½ to 2 hours (first baby)

Third stage of laborThird stage of labor Afterbirth expelled by uterus (placenta and fetal membranes)Afterbirth expelled by uterus (placenta and fetal membranes) Usually baby is alert, looking around the room Usually baby is alert, looking around the room

Complications and InterventionsComplications and Interventions Midwives, coaches, and medical staff may relieve pain without using medsMidwives, coaches, and medical staff may relieve pain without using meds

Warm whirlpoolWarm whirlpool MassageMassage MusicMusic HypnosisHypnosis BiofeedbackBiofeedback Visual images of the cervix openingVisual images of the cervix opening

Physicians may use meds and interventions, e.g.,Physicians may use meds and interventions, e.g., AnalgesicsAnalgesics Epidural analgesia (spinal injection)Epidural analgesia (spinal injection) AnestheticsAnesthetics Opioids (a.k.a. narcotics)Opioids (a.k.a. narcotics) Induced labor using PitocinInduced labor using Pitocin Cesarean delivery (30%)Cesarean delivery (30%)

Fetal distressFetal distress Mother’s health problemsMother’s health problems Failure for labor to progressFailure for labor to progress Birth canal infectionsBirth canal infections Presence of multiple babiesPresence of multiple babies

Babies at RiskBabies at Risk Premature infantPremature infant – babies are considered premature if born before – babies are considered premature if born before

the end of week 37the end of week 37 Premature labor is triggered byPremature labor is triggered by

Infection, multiple gestations (twins or triplets), fetus abnormalities, Infection, multiple gestations (twins or triplets), fetus abnormalities, death of fetus, uterine or cervical abnormalities, serious disease in death of fetus, uterine or cervical abnormalities, serious disease in mothermother

Seriously premature babies suffer fromSeriously premature babies suffer from Breathing problems, anemia, brain hemorrhages, feeding problems, Breathing problems, anemia, brain hemorrhages, feeding problems,

instability in temperatureinstability in temperature

Babies born small for date are at risk forBabies born small for date are at risk for Neurological deficiencies, structural problems with body parts, difficulty Neurological deficiencies, structural problems with body parts, difficulty

with breathing and visionwith breathing and vision Low birth size and weight after sufficient time in the uterus is often Low birth size and weight after sufficient time in the uterus is often

caused by exposure to teratogens or chromosomal abnormalitiescaused by exposure to teratogens or chromosomal abnormalities

Developmental Care for Developmental Care for Babies at RiskBabies at Risk

Fragile infants needFragile infants need Medical staff toMedical staff to

Reduce their exposure to noise and lightReduce their exposure to noise and light Regulate the amount of handlingRegulate the amount of handling Position them in a way that increases circulationPosition them in a way that increases circulation

Parents toParents to Stay actively involved during infant careStay actively involved during infant care Stay informed of the infant’s needsStay informed of the infant’s needs Arrange a proper activity schedule to ensure sleep and restArrange a proper activity schedule to ensure sleep and rest Cuddle and carry them often and for long periodsCuddle and carry them often and for long periods Swaddle them in a blanket with arms bent allowing the baby’s hands Swaddle them in a blanket with arms bent allowing the baby’s hands

to reach their mouth for sucking to reach their mouth for sucking Massage themMassage them Stay informed through early childhood developmentStay informed through early childhood development

Enhancing Caregivers’ Sensitivity Enhancing Caregivers’ Sensitivity

to Newborn Infantsto Newborn Infants Talk about the baby’s sensations (physiological detection of Talk about the baby’s sensations (physiological detection of

environmental stimuli) and perceptions (interpretation of sensations)environmental stimuli) and perceptions (interpretation of sensations) Point out the newborn’s states of arousal (sleepiness and Point out the newborn’s states of arousal (sleepiness and

wakefulness) and reflexes (automatic motor response to stimuli) wakefulness) and reflexes (automatic motor response to stimuli) experienced throughout the dayexperienced throughout the day

Encourage parents to become aware of their baby’s responses to Encourage parents to become aware of their baby’s responses to certain stimulicertain stimuli

Suggest different types of soothing techniques, i.e., listening to a Suggest different types of soothing techniques, i.e., listening to a clothes dryer, nursing, sleeping on father’s chest, riding in a carclothes dryer, nursing, sleeping on father’s chest, riding in a car

Model sensitivity to baby’s interaction preferencesModel sensitivity to baby’s interaction preferences

Teach parents how to perform care-taking functions, e.g., feeding, Teach parents how to perform care-taking functions, e.g., feeding, bathing, diaper changing, and proper carrying or holdingbathing, diaper changing, and proper carrying or holding

Offer continued support for parents of fragile infantsOffer continued support for parents of fragile infants