PSYC 2314 Lifespan Development

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PSYC 2314Lifespan Development

• Chapter 4
• Prenatal Development and Birth

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Stages of Prenatal Development

• Germinal period
• First two weeks
• Within hours after conception, the one-cell
  zygote travels down the Fallopian tube toward the
  uterus and begins the process of cell division
  and growth

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Stages of Prenatal Development

• Germinal period
• Soon, differentiation occurs, a process first
  clearly seen when the multiplying cells separate
  into two distinct masses, one inside the other.
  The outer cells will become the placenta the
  inner cells form a nucleus that will become the
  embryo.
• If all goes well, implantation of the cell mass
  occurs.

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Stages of Prenatal Development

• Embryonic period
• Begins as the organism begins differentiating
  into three layers, each of which will become a
  key body system.
• A fold in the outer layer of cells becomes the
  neural tube, which will become the brain and
  spinal column (the central nervous system).

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Stages of Prenatal Development

• Embryonic period
• In the fourth week, the cardiovascular system is
  functioning the eyes, ears, nose, mouth start to
  form.
• At five weeks, the arm and leg buds appear and
  the embryo is about ¼ inch long.
• By the end of the second month, the developing
  organism weighs about 1 gram, is 1 inch long, and
  has all the basic organs (except the sex organs)
  and features of a human being.

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Stages of Prenatal Development

• Fetal period
• During the third month, the sex organs begin to
  take shape.
• During the early weeks of life, the placenta
  develops rapidly. This organ connects the
  circulatory system of the mother with that of her
  growing embryo, allowing nourishment to flow to
  the developing organism and transporting wastes
  away.

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Stages of Prenatal Development

• Fetal period
• In the mid three months, the systems develop more
  fully. The crucial factor in the fetuss
  attaining the age of viability, beginning at
  about 22 weeks, is brain maturation, which is
  essential to the regulation of the basic body
  functions of breathing, sucking, and sleeping.
• By 28 weeks, the typical fetus weighs about 1,300
  grams (3 lbs.) and has a greater than 90 chance
  of survival.

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Stages of Prenatal Development

• Fetal period
• During the last 3 months, the respiratory and
  cardiovascular systems mature dramatically.
• Weight gain during last weeks stores fat, which
  will provide a layer of insulation when the child
  is no longer surrounded by the mothers warmth.
  The weight gain also provides nourishment and
  vitamins that will be used until the mothers
  breast milk is fully established.

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Fetuss Responses

• Physiological interdependence
• Fetal movements
• Hearing

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Teratology

• The scientific study of birth defects
• A science of risk analysis, which attempts to
  evaluate what factors can make prenatal harm
  more, or less, likely to occur.
• Teratogenssubstances or conditions as viruses,
  drugs, chemicals, stressors, and environmental
  hazards.

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3 Crucial Factors

• Timing of exposure
• Amount of exposure
• Developing organisms genetic vulnerability to
  damage from the substance

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Critical periods

• Physical structure and form-embryonic
• For conditions (such as severe malnutrition) and
  substances (such as heroin), that disrupt and
  destabilize the overall functioning of the
  womans body, there are two critical periods
  the very beginning and the near the end of the
  pregnancy

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Critical periods

• At the very beginning, when stress during the
  germinal period can impede implantation.
• Near the end, when the fetus most needs to gain
  weight and when the cortex of the brain is
  developing, making the fetus particularly
  vulnerable to damage that can cause learning
  disabilities.

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Critical periods

• Also, instability of the mothers body systems
  (chills, shakes, etc.) can loosen the placenta or
  cause hormonal changes, both of which can
  precipitate birth.
• For behavioral teratogens there is no safe
  period. The brain and nervous system can be
  harmed throughout the prenatal development.

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Amount of Exposure

• Threshold effect the substance is virtually
  harmless until exposure reaches a certain
  frequency or dosage.
• Interaction effect the combination of threshold
  teratogens taken together may make them more
  harmful at lower dosage levels than they would be
  individually.

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Genetic Vulnerability

• Susceptibility to alcoholism involves a
  genetically related defect in a specific enzyme.
• A deficiency in folic acid in the mothers diet
  may also result in genetic defects.
• Males not only have a higher rate of teratogenic
  birth defects and later teratogen-related
  behavioral problems, but also a higher rate of
  spontaneous abortions.

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Teratogens

• Rubella (German measles)
• If contracted early in pregnancy, it can cause
  blindness, deafness, heart abnormalities, and
  brain damage.
• Human Immunodeficiency Virus (HIV)
• A pregnant women with HIV may pass the virus on
  to her fetus either during pregnancy or
  childbirth. Infants who have HIV will eventually
  develop pediatric AIDS.

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Teratogens

• Psychoactive Drugs
• Slow fetal growth, contribute to premature labor,
  and may produce both short- and long-term brain
  deficits.

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Teratogens

• Alcohol Consumption
• Large doses of alcohol can trigger the physical,
  behavioral, and mental symptoms of fetal alcohol
  syndrome (FAS).
• Even moderate alcohol consumption during
  pregnancy (more than ½ ounce of absolute alcohol)
  can produce the intellectual impairment of fetal
  alcohol effects (FAE).

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Teratogens

• Smoking
• Increases the risk of abnormalities and reduces
  birthweight and size babies whose mothers smoked
  are shorter at birth and in the years to come.
  They are also more likely to have respiratory
  problems.

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Teratogens

• Drugs
• Prenatal exposure to marijuana has been linked to
  central nervous system impairment.
• Exposure to heroin causes slower fetal growth and
  premature labor.
• Cocaine use during pregnancy retards fetal
  growth, increase the risk of problems with the
  placenta, and often leads to early learning
  difficulties.

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Protective Measurements

• Complete abstinence from drugs even before
  pregnancy
• Abstinence after the first month
• Moderation throughout pregnancy (if abstinence is
  not possible)
• Minimizing maternal stress by seeking social
  support
• Obtain good postnatal care

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Birthweight

• Low birthweight (LBW)
• Less than 5 ½ lbs.
• Preterm
• LBW infants who are born more than 3 weeks early
• SGA (small for gestational age)
• Infants born close to the due date but weighing
  less than most full-term newborns.

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Poverty and LBW

• Pregnant women at the bottom of the SES are more
  likely to be ill, malnourished, teenaged, and
  stressed
• If they are employed, their jobs often require
  long hours of physically stressful work, exactly
  the kind that correlates with preterm and SGA
• They often receive late or inadequate prenatal
  care, breathe polluted air, live in overcrowded
  conditions, ingest unhealthy substances

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Normal Birth

• Begins at about the 266th day after conception,
  when the fetuss brain signals the release of
  hormones that trigger uterine contractions in the
  mother.
• The first stage of labor (until the babys head
  emerges from the birth canal) usually lasts 6
  hours in first births and 3 hours in subsequent
  births.

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Apgar Scale

• Used to assign score between 0 and 2 to the
  newborns heart rate, breathing, muscle tone,
  color, and reflexes at 1 minute after birth and
  again at 5 minutes.
• A score of 7 or better indicates the newborn is
  not in danger below 7, infant needs help in
  establishing normal breathing and below 4, the
  baby is in critical condition.

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Medical Attention/Intervention

• Medical procedures are overused episiotomies
  and C-sections
• Routine procedures IV, fetal monitoring, are
  rooted in tradition rather than in medical
  necessity.

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Birth Complications

• Birth complications are more likely if the fetus
  is already at risk because of low weight, preterm
  birth, genetic abnormality, or teratogenic
  exposure.
• Researchers now realized that cerebral palsy
  (difficulties with movement control resulting
  from brain damage) results from genetic
  vulnerability, worsened by teratogens and a
  birthing process that includes anoxia (a
  temporary lack of oxygen).

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Birth Complications

• Many hospitals now provide high-risk infants with
  regular massage and soothing stimulation.
• When they are brought home, high-risk infants are
  often more distractible, less obedient, and
  slower to talk. However, long-term impairment is
  not inevitable.

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Parent-newborn Bond

• Emphasize the tangible as well as the intangible
  attachment of parent to child in the early
  moments after birth.
• Diane Eyer-bonding is a social construction that
  developed as a reaction against the
  medicalization and depersonalization of
  traditional hospital births.
• Extensive research has shown that the events
  right after birth are just one episode in a
  long-term process of bonding between parent and
  child.