Prenatal Development and Birth

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Part I
Chapter Four

• Prenatal Development and Birth

From Zygote to Newborn Risk Reduction The Birth
Process
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Prenatal Development and Birth

• The majority of newborns are male (52), and more
  are Chinese (30) yet every baby is unique
  every area of development is directly relevant to
  the 150 million babies born in the world every
  year there are generalities and variation but
  expect to be awed by the miracle of birth.

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From Zygote to Newborn

• Prenatal development is divided into three main
  periods
• germinal Period (0-2 weeks)
• embryonic Period (3-8 weeks)
• fetal Period (9 weeks-birth)

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From Zygote to Newborn

• Germinal The First 14 Days
• Conception occurs in fallopian tubes
• Cell differentiation and multiplication
• 42 of conceptions successfully implant in uterus
  
• blastocyst
• when cells take on distinct characteristics and
  gravitate toward particular positions, the entire
  cell mass (still very fragile and tiny)
• placenta
• the organ that surrounds the developing embryo
  and fetus, sustaining life via the umbilical
  cordattached to the wall of the uterus
• Implantation
• the process, beginning about 10 days after
  conception, which the developing organism burrows
  into the placenta that lines the uterus, where it
  can be nourished and protected as it continues to
  develop.

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From Zygote to Newborn

• Embryo from the third through the eighth week
• embryonic period (3-8 weeks)
• major organs develop
• at eight weeks, organism is less than 2? long

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From Zygote to Newborn

• Fetus From the Ninth Week Until Birth
• Fetal Period (9 weeks-birth)
• Sex organs develop
• Brain development is significant
• Age of viability occurs around 22 weeks
• fetus
• a developing organism from the ninth week after
  conception until birth

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From Zygote to Newborn

• The Third Month
• the fetus has all its body parts
• weighs approximately 3 ounces, about 3 inches
  long
• growth is rapid
• fetus is too small survive outside of the womb

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From Zygote to Newborn

• The Middle Three Months Preparing to Survive

• in the fourth, fifth and sixth months the
  heartbeat becomes stronger
• the cardiovascular system more active
• the brain increases about six times in size
• age of viability
• twenty-two weeks after conception a fetus can
  survive outside the mothers uterus if
  specialized medical care is available

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From Zygote to Newborn

• The Final Three Months From Viability to Full
  Term
• Viability
• life outside the womb is possible
• born in the seventh month requires intensive
  hospital care and life-support systems
• difference between preterm and newborn is the
  maturation of neurological, respiratory,
  cardiovascular systems

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Risk Reduction

• toxins, illnesses and experiences can harm a
  developing person before birth
• teratology
• a science of risk analysis, the study of birth
  defects
• teratogens
• Agents and conditions that can harm the prenatal
  brain, impairing the future childs intellectual
  and emotional functioning
• behavioral teratogens
• Agents and conditions that can harm the prenatal
  brain, impairing the future childs intellectual
  and emotional functioning

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Risk Reduction

• Determining Risk
• risk analysis
• the science of weighting the potential effects of
  a particular event, substance, or experience to
  determine the likelihood of harm
• Timing of Exposure
• critical period
• In prenatal development, the time when a
  particular organ or other body part of the embryo
  or fetus is most susceptible to damage by
  teratogens

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Risk Reduction

• Amount of Exposure
• Threshold effect
• a situation in which a certain teratogen is
  relatively harmless in small doses but becomes
  harmful once exposure reaches a certain level
  (the threshold)
• Interaction effect
• the result of a combination of teratogens.
  Sometimes risk is greatly magnified when an
  embryo or fetus is exposed to more than one
  teratogen at the same time

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Risk Reduction

• Protective Measures
• Benefits of Prenatal Care

14
The Birth Process

• The Newborns First Minutes
• Apgar scale
• a quick assessment of a newborns body
  functioning.
• color
• heart rate
• reflexes
• muscle tone
• respiratory effort

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The Birth Process

• Variations
• medical Intervention
• cesarean section
• fetus is removed through incisions in the
  mothers abdomen and uterus
• birth complications
• includes anything in the newborn, the mother, or
  the birth process itself that requires special
  medical attention
• anoxia
• a lack of oxygen that, if prolonged during
  birth, can cause brain damage or death to the baby

16
The Birth Process

• Low Birthweight (LBW)
• the average weight of a newborn is 7½ lbs.
• LBW is considered less than 5½ lbs.
• preterm is less than 35 weeks
• lifestyle choices
• e.g., cigarette smoking accounts for 25 of LBW
  births worldwide!
• maternal malnutrition
• multiple births
• prescription drugs
• unknown causes

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The Birth Process

• Social Support
• Mother, Father, and a Good Start
• Help from fathers
• parental alliance cooperation between a mother
  and a father based on their mutual communication
  to their children the parents agree to support
  each other in their shared parental roles
• Postpartum Depression
• 8-15 of women experience postpartum depression,
  a sense of inadequacy and sadness after birth.
• includes irritability, sleep and eating
  disruptions, sadness, feeling overwhelmed and
  inadequate as a mom, no interest or overly
  worried about baby.