Prenatal Development and the Newborn Period

1
Prenatal Developmentand the Newborn Period

• How Children Develop (3rd ed.)
• Siegler, DeLoache Eisenberg
• Slides have been adapted.
• Chapter 2

2
Overview Major Topics

• I. Prenatal Development
• II. The Birth Experience
• III. The Newborn Infant

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Guiding Questions

• What changes occur during prenatal development?
• How does the environment contribute to prenatal
  development?
• How does the developing childs behavior
  contribute to its own development?
• Can learning occur during the prenatal period?
• What is daily life like for the newborn?
• What special risks threaten the developing
  newborn?

4
Changing Ideas Over Time

• Aristotle rejected the prevailing idea that the
  individual was preformed at the start of life in
  favor of epigenesis, the idea that there is an
  emergence of new structures and functions during
  development.

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• What changes occur during prenatal development?

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The Reproductive Process

• An egg is launched from one of the womans
  ovaries into the fallopian tube.
• If sexual intercourse takes place near the time
  the egg is released, then conception will be
  possible.

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Conception

• Results from the union of two gametes, the egg
  and the sperm
• Gametes are produced through a specialized cell
  division, which results in each gametes having
  only half the genetic material of all other
  normal cells in the body.
• Population sex differences begin at conception.
  More males are conceived, but males are more
  vulnerable after this point.

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The Zygote

• After conception, the fertilized egg, or zygote,
  has a full complement of human genetic material,
  half from each parent.

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Processes Occurring During Prenatal Development

• These processes transform a zygote into an embryo
  and then into a fetus.
• Cell division results in the proliferation of
  cells.
• Cell migration is the movement of cells from
  their point of origin to somewhere else in the
  embryo.
• Cell differentiation transforms the embryos
  unspecialized stem cells into different types of
  cells.
• Apoptosis, genetically programmed cell death,
  also enables prenatal development.

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Early Development

• By the 4th day after conception, the zygote
  arranges itself into a hollow sphere of cells
  with a bulge of cells, the inner cell mass, on
  one side.
• The inner cell mass eventually forms into the
  embryo.

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The Embryo

• After implantation, the inner cell mass becomes
  the embryo and the rest of the cells develop
  into its support system.
• The neural tube is a U-shaped groove formed
  from the top layer of differentiated cells in
  the embryo.
• It eventually becomes the brain and the spinal
  cord.

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• How does the environment contribute to prenatal
  development?

13
Teratogens

• Environmental agents that have the potential to
  cause harm during prenatal development.
• Timing is a crucial factor in the severity of
  the effects of potentially harmful agents.
• Many agents cause damage only if exposure
  occurs during a sensitive period in development.

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• Most teratogens show a dose-response relation.
• Increases in exposure to potential teratogens are
  associated with greater probabilities of fetal
  defects and with more severe problems.
• Individual differences also influence the effects
  of teratogens.

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Teratogens

• Identifying teratogens is made difficult by the
  existence of sleeper effects in which the impact
  of a given agent may not be apparent for many
  years.
• Teratogens include legal as well as illegal
  substances...

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Legal Drugs Cigarettes

• Cigarette smoking during pregnancy is linked to
  retarded growth and low birth weight.
• Cigarette smoking has also been linked to SIDS
  (sudden infant death syndrome), although the
  ultimate causes of SIDS are still unknown.
• Parents can reduce the risk of SIDS by not
  smoking, putting babies to sleep on their backs
  rather than on their stomachs, using firm
  mattresses and no pillows as bedding for infants,
  and avoiding wrapping infants in lots of blankets
  or clothing.

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Legal Drugs Alchohol

• Maternal alcoholism can lead to fetal alcohol
  spectrum disorder (FASD), which is associated
  with mental retardation, facial deformity, and
  other problems.

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Illegal Drugs

• Approximately 4 of pregnant women in the U.S.
  use illicit drugs.
• Marijuana is suspected of affecting memory,
  learning, and visual skills after birth.
• Cocaine-exposed children have reported cognitive
  and social deficits.

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Environmental Pollutants

• Toxic metals, synthetic hormones, and various
  ingredients of plastics, pesticides, and
  herbicides can be teratogenic.
• PCBs (polycholorinated biphenyls) have been
  associated with small head size as newborns and
  slightly lower IQ scores as long as 11 years
  later.

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Occupational Hazards

• Many women have jobs that bring them into contact
  with potentially hazardous elements (e.g.,
  automobile exhaust, pesticides, chemicals, noise
  pollution).

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Maternal Factors

• The age, nutrition, disease, and emotional state
  of the mother have an impact on prenatal
  development
• Infants born to girls 15 years or younger are
  three to four times more likely to die before
  their first birthday than are those whose mothers
  23-29 years of age.
• An inadequate supply of specific nutrients or
  vitamins such as folic acid can have dramatic
  consequences.
• A variety of diseases including sexually
  transmitted diseases present hazards to the
  fetus.
• A womans emotional state can
  affect her fetus.

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Protecting the Fetus

• The placental membrane is a barrier against some,
  but not all toxins and infectious agents.
• The amniotic sac, a membrane filled with fluid in
  which the fetus floats, provides a protective
  buffer for the fetus

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• How does the developing childs behavior
  contribute to its own development?

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The Role of Hormones

• Hormones play a crucial role in sexual
  differentiation.
• All human fetuses can develop either male or
  female genitalia, depending on the presence or
  absence of testosterone.

25
Fetal Behavior

• By 12 weeks after gestation, most of the
  movements that will be present at birth have
  appeared.
• Prenatal to postnatal continuity
• Swallowing amniotic fluid promotes the normal
  development of the palate and aids in the
  maturation of the digestive system.
• Movement of the chest wall and pulling in and
  expelling small amounts of amniotic fluid help
  the respiratory system become functional.

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Behavioral Cycles

• Become stable during the second half of pregnancy
• Circadian rhythms are also apparent
• Near the end of pregnancy, sleep and wake states
  are similar to those after birth

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• Can learning occur during the prenatal period?

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Fetal Sensory Experience

• Sensory structures are present relatively early
  in prenatal development and play a vital role in
  fetal development and learning.
• Visual experience is negligible.
• Fetus experiences tactile stimulation as a result
  of its own activity, and tastes and smells the
  amniotic fluid.
• It responds to sounds from at least the 6th
  month of gestation.

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Evidence of Fetal Learning

• At 32 weeks gestation, the fetus decreases
  responses to repeated or continued stimulation, a
  simple form of learning called habituation.

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Evidence of Fetal Learning

• Newborn infants have been shown to recognize
  rhymes and stories presented before birth.
• Newborns also prefer smells, tastes, and sound
  patterns that are familiar because of prenatal
  exposure.

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• What is daily life like for the newborn?

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Newborn States of Arousal

• State The infants level of arousal and
  engagement in the environment
• Ranges from deep sleep to intense activity
• Is an important influence in the newborns
  exploration of the world

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Six States of Arousal

1. Active sleep
2. Quiet sleep
3. Crying
4. Active awake
5. Alert awake
6. Drowsing

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Newborn States
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Safe Sleep is Essential

• Newborns sleep twice as much as young adults
• The pattern of two different sleep states changes
  dramatically

• REM (rapid eye movement) sleep an active sleep
  state associated with dreaming in adults and is
  characterized by quick, jerky eye movements under
  closed lids
• Non-REM sleep a quiet or deep sleep state
  characterized by the absence of motor activity or
  eye movements and by regular, slow brain waves,
  breathing, and heart rate

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REM Sleep

• REM sleep constitutes fully 50 of a newborns
  total sleep time and declines rapidly to only 20
  by 3 or 4 years of age.
• According to autostimulation theory, brain
  activity during REM sleep in the fetus and
  newborn makes up for natural deprivation of
  external stimuli and facilitates the early
  development of the visual system.

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Crying

• Early in infancy, crying reflects discomfort or
  frustration.
• Crying gradually becomes more of a communicative
  act.
• With experience, parents become better at
  interpreting the characteristics of the cry
  itself.

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Crying

• Many effective soothing techniques, including
  swaddling, involve moderately intense and
  continuous or repetitive stimulation.

• Parents of babies with colic should seek social
  support and relief from frustrationand remember
  that colic typically ends within a few months.

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• What special risks threaten the developing
  newborn?

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Infant Mortality

• Death during the first year after birth (infant
  mortality) has become a relatively rare event in
  the Western industrialized world.
• However, rates in the United States are the 20th
  highest in the world.
• African-American infants are more than twice as
  likely to die before their first birthday as
  Euro-American babies.
• Poverty and lack of health insurance are
  associated with high rates of infant mortality.

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Low Birth Weight

• Infants weighing less than 5.5 pounds (2,500
  grams) are considered to be of low birth weight
  (LBW).
• LBW infants born at or before 35 weeks after
  conception are described as premature.
• Other LBW infants are referred to as small for
  gestation age (SGA) when their birth weight is
  substantially less than the norm for their
  gestational age.

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Low Birth Weight

• As a group, LBW babies experience more medical
  complications, have more developmental
  difficulties, and present special challenges for
  parents.
• However, the majority of LBW babies turn out
  quite well.
• Extensive parent contact and more touch for
  infants in neonatal intensive care are widely
  used interventions.

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Parenting LBW Infants

• Parenting LBW babies presents special challenges
  due to parents feelings of guilt and inadequacy,
  the stress of intensive care treatment, and the
  infants disorganized states.
• Parents benefit from understanding that their
  preterm infants development will not follow the
  same timetable as that of a full-term infant, by
  learning more about infant development, and by
  seeking social support and intervention programs.

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Multiple-Risk Models

• Risk factors tend to occur together.
• A negative outcome is more likely when there are
  multiple risk factors.
• Despite multiple risk factors, however, some
  individuals do well.

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Poverty as a Developmental Hazard

• The existence of multiple risks is strongly
  related to socioeconomic factors.
• In many countries, minority families are
  overrepresented in the lowest SES levels.

46
Risk Resilience

• Developmental resilience refers to successful
  development in the face of multiple and seemingly
  overwhelming developmental hazards.
• Resilient children often experience responsive
  care from a particular caregiver and possess
  personal characteristics such as intelligence and
  responsiveness to others.