Transcript Overview of Chapter 11

Chapter 4: Prenatal
Development and Birth
MODULES
4.1 From Conception to Birth
4.2 Influences on Prenatal
Development
4.3 Happy Birthday!
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Module 4.1 Conception
to Birth
LEARNING OBJECTIVES
Recount what happens to a fertilized egg in
the first two weeks after conception.
Describe when body structures and internal
organs emerge in prenatal development.
Note when body systems begin to function
well enough to support life.
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Period of the Zygote
Begins when egg is fertilized in the
fallopian tube.
Period of rapid cell division.
Ends 2 weeks later when the zygote is
implanted in the wall of the uterus.
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Period of the Zygote
Germ disc: a small cluster of cells near the zygote’s center that develops
into a baby.
Placenta: a uterine structure for exchanging nutrients and wastes between
mother and baby.
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Period of the Embryo
From 3 to 8 weeks after conception.
Body parts are formed during this period
-Ectoderm
-Mesoderm
-Endoderm
Embryo rests in the amnion filled with amniotic
fluid.
Umbilical cord joins embryo to placenta.
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Period of the Fetus
From 9 weeks after conception to birth.
Increase in size and systems begin to function
-Cephalocaudal
-Proximodistal
Age of viability: 22 to 28 weeks.
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Module 4.2 Influences on Prenatal
Development
LEARNING OBJECTIVES
Explain how prenatal development is influenced by a pregnant
woman’s nutrition, the stress she experiences while pregnant,
and her age.
Define what a teratogen is, and state what specific diseases,
drugs, and environmental hazards can be teratogens.
Detail exactly how teratogens influence prenatal development.
Summarize how prenatal development can be monitored and
how abnormal prenatal development can be corrected?
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General Risk Factors
Nutrition: adequate amount of food, protein, vitamins,
& minerals.
-Folic acid and spina bifida.
Stress: decreases oxygen to fetus and weakens
mother’s immune system.
-Workplace stress.
Mother’s Age: neither too young, nor too old.
-More women are having babies after the age of 30.
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Teratogens: Diseases, Drugs,
and Environmental Hazards
Thalidomide (http://www.thalidomide.ca).
Many diseases pass through the placenta directly and
attack the fetus.
Potentially dangerous drugs not limited to cocaine but
include alcohol and caffeine.
-Fetal alcohol spectrum disorder (FASD)
Environmental hazards are treacherous because
we’re often unaware of their presence.
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How Teratogens Influence
Prenatal Development
Not universally harmful.The impact of a teratogen
depends upon the genotype of the organism.
The impact of teratogens changes over the course of
prenatal development.
Each teratogen affects a specific aspect (or specific
aspects) of prenatal development.
Damage from teratogens is not always evident at birth
but can appear later in life.
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Effects of Teratogens
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Prenatal Diagnosis and
Treatment
Diagnosis: ultrasound, amniocentesis,
and chorionic villus sampling (CVS)
can detect physical deformities and
genetic disorders.
Treatment: fetal medicine and genetic
engineering are experimental (PKU).
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Prenatal Diagnosis
Amniocentesis
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Chorionic Villus Sampling
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Module 4.3 Happy Birthday!
LEARNING OBJECTIVES
List the stages in labour and delivery.
Describe “natural” ways of coping with the pain of
childbirth and state under what circumstances
childbirth at home might be safe.
Summarize how we determine whether a baby is
healthy and what behavioral states are common in
newborns.
Identify some complications that occur during birth.
List the characteristics of postpartum depression and
its effects.
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Labour and Delivery
Stage 1: starts when the muscles of the uterus contract and ends when
the cervix is fully enlarged (about 10 cm).
Stage 2: baby is pushed down the birth canal.
-Crowning
- Breech presentation
Stage 3: placenta is expelled.
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Approaches to Childbirth
Childbirth classes provide information and teach pain control
through deep breathing, imagery, and supportive coaching.
Mothers who attend classes use less medication during labour
and feel more positive about labour and birth.
In the last 40 years, many Canadian women have used more
“natural” or prepared approaches to childbirth, viewing labour
and delivery as life events to be celebrated, rather than a
medical procedure to endure.
3% of Canadian families chose to have babies at home with
the help of a midwife.
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Birth Complications
Lack of oxygen (anoxia): Often leads to surgical
removal of the fetus (C-section).
Placental abruption can also lead to hypoxia.
Premature and Small-for-date infants.
Prematurity is less serious than small-for-date.
Low birth weight can result in infant mortality.
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The Newborn
Assessing the newborn: Apgar to assess
newborns’ health; NBAS for a comprehensive
assessment of infants.
4 primary states: alert inactivity, waking activity,
crying, sleeping.
Half of newborns’ sleep is REM (i.e. stimulation
of the infant’s brain).
Sleeping on one’s back may prevent SIDS.
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Postpartum Depression
Half of all new moms feel some irritation,
resentment, and crying.
10-15% feel more severe postpartum
depression.
Maternal postpartum depression is
characterized by feelings of low self-worth,
disturbed sleep, poor apathy and appetite.
Postpartum depression affects warmth and
enthusiasm of mothering.
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Conclusions
All new mothers need support from
family and friends.
Postpartum depression must be
treated.
Children of depressed mothers are at
an increased risk of developing
depression and behavioral problems.
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