life span 4
TRANSCRIPT
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CHAPTER 4
PRENATAL DEVELOPMENT AND BIRTH
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Learning Objectives
How does developmentunfold during the
prenatal period from
conception until thetime of birth?
How does prenatalbehavior of the fetus
relate to postnatalbehavior of the infant?
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Prenatal Development
Time of fastest developmentin life span
Environment extremely
important Conception
Ova travels from ovary to
uterus
Penetration by 1 of 300-
500 sperm
Outcome: Single-celled
ZYGOTE
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Prenatal Stages
Germinal period: Days 1-14 Implantation: One-half are
successful
Miscarriage: 15% to 50%
Embryonic period: 3rd to 8th week Organogenesis, Sexual
differentiation
Fetal period: 9th week birth
Proliferation, Migration Differentiation of stem cells
Ends in tremendous brain
development
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Learning Objectives
How and when do variousteratogens affect the
developing fetus?
How can you summarize theeffects of teratogens during theprenatal period?
How do maternal age,emotional state, and nutrition
affectprenataland neonataldevelopment?
What about the fathers state -can this influence
development?
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Prenatal Environment
Reciprocal influence Person and environment
Good and bad influences
important Teratogen: Environmental agent
Harms the developing fetus
Critical Period: Organogenesis
Dosage and duration
Genetic make-up:
Susceptibility
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The critical periods of prenatal development. Teratogens are more likely toproduce major structural abnormalities during the third through the eighth
prenatal week. Note, however, that many organs and body parts remainsensitive to teratogenic agents throughout the nine-month prenatal period
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Teratogens: Drugs
Thalidomide (for morningsickness)
All or parts of limbs missing
Tobacco: Miscarriage, low birthweight, SIDS, slows fetal growth Alcohol: FAS
Small, facial deformities,
retardation
Cocaine: Processing difficulties
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(A)Characteristic features of a child with fetal alcohol syndrome (FAS).
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(B) Child with FAS, illustrating many features in the drawing. Such children mayalso have cardiovascular and limb defects.
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Teratogens - Diseases
Rubella (GermanMeasles)
Blind, deaf, heart, brain
Syphilis: Miscarriage,blind, deaf, heart, brain After 18th week
AIDS: Mothers transmit tobabies (15%-35%)
Prenatally, perinatally,
postnatally
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Teratogens: Environmental Hazards
Radiation: MR,leukemia, cancer,
mutations, spontaneous
abortions, etc.
Avoid X-rays when
pregnant
Pollutants
In air and water Lead: MR (also
postnatally)
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The Mothers State
Age: Typically age 16-35 15 or younger dont seek prenatal
care
Birth complications, low birth
weight Over 35:Miscarriage, Down
Syndrome (fathers age also)
Emotion: Stress can stunt fetal growth
Positive outlook most helpful
Nutrition: 25-35 lb weight gain Malnutrition: Smaller neurons,
brain, child
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The three stages of labor: Stage 1: (a) Contractions of the uterus cause dilation andeffacement of the cervix. (b) Transition is reached when the frequency and strength of thecontractions are at their peak and the cervix opens completely. Stage 2: ( c) The motherpushes with each contraction, forcing the baby down the birth canal, and the head appears.
(d) Near the end of Stage 2, the shoulders emerge and are followed quickly by the rest of thebabys body. Stage 3: (e) With a few final pushes, the placenta is delivered.
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The Fathers State
Research limited except forgenetic contribution
Fathers age can also be influential Over 35: Increased number
miscarriages, heart defects,Down Syndrome
Over 50: Higher risk for
schizophrenia
Exposure to environmental toxins Radiation, anesthetic gases,
pesticides
Damage to genetic material in
sperm
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Learning Objectives
What is the typicalperinatalenvironment
like?
What hazards can occur
during the birth
process?
What is the birthexperience like from the
mothers and fathersperspectives, and from
different cultural
perspectives?
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Newborn
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The Perinatal Environment
Birth Process: Three stepprocess
Possible Hazards
Anoxia: Oxygenshortage: Can be
severe
Complicated delivery
Cesarean(C)section
Medications: Can reachbaby
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The Mothers Experience
Severe pain, anxiety 77% rate it as
positive experience
Psychological factors Attitude, knowledge,
support
Medication: Sedatives,anesthetics, pitocin
Cultural factors
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The Fathers Experience
Accepted, expected in delivery rooms Attend prenatal classes with wife Experience described as a significant
event Anxiety, stress common duringdelivery
Relief, pride, joy when baby is born
Sometimes depression following birth Fathers also need support Disappointed if sex does not resume
soon
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The Neonatal Environment
Culture, early socialization, health status E.g., low birth-weight babies (8% in US)
Less than 5 lbs
Strongly linked to low SES
Environment: Neonatal intensive care
Risk: Blindness, deafness, CP, autism,cognitive, and later academic problems
Parenting must be attentive, responsive
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Modern technology permits survival of younger and smaller babies, but many experts believe we
have reached the lowest limits of viability at 23-24 weeks gestation.
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Low Birth-Weight Babies
< 5 pounds: Small for date orpreterm Leading cause of infant mortality
8% of all births, 65% of all infant
deaths
Factors: Low SES, smoking, stress,multiples
Worse for minority, poverty, single-parent children
For most, significant catch-up
growth
Low Birth-Weight Infants
Greater risk for blindness, deafness,CP, autism, health problems -
especially respiratory problems
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Factors Helpful for LBW Infants
Breastfeeding, skin-to-skin contact, massage Responsive parenting, intellectual stimulation Early intervention programs work with parents
Childcare education and support Growth-enhancing home environment
Consistently attentive, responsive parenting
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Risk and Resilience
Not all high-risk infants haveproblems
Werner: Kauai Longitudinalstudy(40 yrs)
Findings: Effects decrease over time
Outcomes depend onpostnatal environment
Protective factors
Personal resources Supportive postnatal
environment