Chapter Four

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Chapter Four

• Prenatal Development and Birth

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From Zygote to Newborn

• Germinal
• Embryo
• Fetus

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Germinal Stage First Fourteen Days

• Zygote divides and keep dividing (at least
  through the third doubling they are the same)
• At this stage (8 cells) the differentiation takes
  place

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• At about a week after conception the multiplying
  cells separate into two masses
• Outer layer forms a protective circle (later the
  placenta) and will take care of the implantation-
  This forms the connective web
• 58 of all natural conceptions fail to implant
  75 of in vitro fail to implant

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Embyronic Period Three to Eight Weeks

• Inner layer differentiates into three layers
• Outer layer (ectoderm) forms the neural tube
• brain, central nervous system and spinal column

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• Middle layer (mesoderm)- Muscles, skeletal
  structure, etc.
• Inner layer(endoderm)- heart, lungs and other
  organs

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• Period of Vulnerability, a.k.a. Critical Period
• 20of all fetuses spontaneously abort due to
  chromosomal abnormalities
• This is also the time where environmental insults
  can result in abnormalities or structural
  anomalies

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Fetus Nine Weeks to Birth

• Third Month
• Sex organs take shape (Y cell sends signal to
  males Females, no signal)
• Fully shaped by the 12th week
• All body parts there and fetus can move every
  part of body

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• Middle Three Months
• Heartbeat stronger
• Digestive and excretory systems develop more
  fully
• Fingernails, teeth and hair
• Impressive brain growth (6X in size and
  responsive)
• Age of viability - age at which preterm baby can
  survive (22 weeks)
• 26 weeks survival rate 50

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• Last Three Months -Viability to Full Term
• Maturation of the respiratory and cardiovascular
  systems
• Gains weight - 4.5 lbs. in the last 10 weeks

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Risk Reduction

• Despite complexity, most babies are born healthy
• Most hazards can be avoided
• Teratology - study of birth defects
• Teratogens - broad range of substances that can
  cause environmental insults that may result in
  prenatal abnormalities at birth or later in
  learning abilities

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• Determining Risk
• Timing of Exposure -critical period
• Risks that affect womans body- at the very
  beginning and the end
• Amount of exposure - dose and/or frequency
• Threshold effect
• interaction effect
• Genetic vulnerability - folic acid, males more
  vulnerable

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Specific Teratogens

• Diseases
• Rubella
• AIDS
• Medicine and Drugs
• legal and illegal
• FAS

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Low Birthweight

• Too soon
• detached placenta
• unable to accommodate further growth
• Things that disrupt physiological equilibrium
• Too small (SGA)
• Tobacco (25 of SGA births)
• Toxemia (high blood pressure/hypertension)

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• Nutrition and Poverty
• Poorly nourished before and during
• Underweight, undereating and smoking tend to
  occur together
• Many risks correlate with poverty

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The Normal Birth

• Stages of Birth
• First stage ? uterine contractions ? ?cervix
  opens (12-14 hours)
• Transition occurs between these two stages ?
  dont touch me
• Second stage ? head in birth canal ? baby is
  delivered (1 1/2 hours)
• Third stage ? referred to as afterbirth ?
  placenta expelled

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The Newborns First Minutes

• Vernix Caseosa
• Color
• Checking for Problems - Apgar Scale
• Five Factors, 2 points each
• Heart rate
• Breathing
• Color
• Muscle tone
• Reflexes

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• Parents Reaction
• Medical Attention

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Birth Complications

• Anoxia
• Cerebral Palsy
• Intensive Care
• Home

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The Beginning of Bonding

• Long term building of relationship
• Factors affecting ability to bond
• From the mother
• personality/temperament
• social support and work status
• health of the baby
• From the child
• temperament
• health (ability to react to bonding)

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Depression and Love

• Postpartum Depression
• Inadequacy and sadness experienced by 10-20 of
  women
• Hawaii home start program
• Day to day support