Slide 1
4—Prenatal Development
and Birth
•
•
•
•
Prenatal Development
Birth
The Postpartum Period
Summary
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Slide 2
Prenatal Development
• The Course of Prenatal Development
– The Germinal Period
• The period of prenatal development that takes place
in the first two weeks after conception. It includes
the creation of the zygote, continued cell division,
and the attachment of the zygote to the uterine wall.
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Slide 3
Prenatal Development
– The Germinal Period (continued)
• Blastocyst: The inner mass of cells that develops
during the germinal period. These cells later develop
into the embryo.
• Trophoblast: The outer layer of cells that develops
in the germinal period. These cells provide nutrition
and support for the embryo.
• Implantation: Attachment of the zygote to the
uterine wall (10 to 14 days after conception)
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Slide 4
Prenatal Development
• The Course of Prenatal Development
– The Embryonic Period
• The period of prenatal development that occurs 2 to
8 weeks after conception. During the embryonic
period, the rate of cell differentiation intensifies,
support systems for the cells form, and organs
appear.
• The embryo has three layers of cells: endoderm,
ectoderm, and mesoderm.
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Slide 5
Prenatal Development
– The Embryonic Period (continued)
• Endoderm: develops into digestive and respiratory
systems.
• Ectoderm: develops into the nervous system,
sensory receptors, and skin parts.
• Mesoderm: develops into the circulatory system,
bones, muscles, excretory system, and reproductive
system.
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Slide 6
Prenatal Development
– The Embryonic Period (continued)
• Life-support systems develop:
– Amnion: The life-support system that is a bag
or envelope containing a clear fluid in which the
developing embryo floats.
– Umbilical cord: The life-support system
containing two arteries and one vein; connects
the baby to the placenta.
– Placenta: A disk-shaped group of tissues in
which small blood vessels from the mother and
offspring intertwine.
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Slide 7
Prenatal Development
– The Embryonic Period (continued)
• Organogenesis:
– Organ formation that takes place during the first
2 months of prenatal development.
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Slide 8
Prenatal Development
Significant Developments in the Germinal
Period
• Refer to Figure 4.1
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Slide 9
Prenatal Development
The Placenta and the Umbilical Cord
• Refer to Figure 4.2
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Slide 10
Prenatal Development
– The Fetal Period
• The prenatal period of development that begins 2
months after conception and lasts for an average of
7 months.
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Slide 11
Prenatal Development
The Three Trimesters of Prenatal
Development
• Refer to Figure 4.3
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Slide 12
Prenatal Development
– Teratology and Hazards to Prenatal
Development
• Teratogen
– From the Greek word Tera, meaning “monster.” Any
agent that causes a birth defect. The field of study
that investigates the causes of birth defects is called
teratology.
– The severity of damage and type of defect from any
particular teratogen depends on dose, genetic
susceptibility, and time of exposure.
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Slide 13
Prenatal Development
Teratogens and the Timing of Their Effects on
Prenatal Development
• Refer to Figure 4.4
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Slide 14
Prenatal Development
– Teratology and Hazards to Prenatal
Development (continued)
• Prescription and Nonprescription Drugs
– Prescription drugs: Antibiotics, some
antidepressants, some hormones, and Accutane.
– Nonprescription drugs: Diet pills, aspirin, and
caffeine.
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Slide 15
Prenatal Development
– Teratology and Hazards to Prenatal
Development (continued)
• Psychoactive drugs: Act on the nervous system to
alter states of consciousness, modify perceptions,
and change moods.
• Alcohol: Even moderate consumption during
pregnancy can result in fetal alcohol syndrome
(FAS), a cluster of abnormalities such as facial
deformities, defective limbs, face, and heart, below
average intelligence, and mental retardation.
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Slide 16
Prenatal Development
– Teratology and Hazards to Prenatal
Development (continued)
• Psychoactive drugs: Nicotine
– Adverse effects prenatally, perinatally, and
postnatally
– Preterm births, low birth weight, fetal and
neonatal deaths, respiratory problems, and
sudden infant death syndrome (SIDS)
– Possibly poor language and cognitive skills, and
ADHD
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Slide 17
Prenatal Development
– Teratology and Hazards to Prenatal
Development (continued)
• Psychoactive drugs: Illegal drugs
– Cocaine: Children are likely to develop
neurological and cognitive deficits.
– Marijuana: Possible deficits in memory and
information processing..
– Heroin: Newborns experience withdrawal
symptoms; later behavioral problems and
attention deficits.
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Slide 18
Prenatal Development
– Teratology and Hazards to Prenatal
Development (continued)
• Incompatible blood types
• Maternal diseases: Rubella, syphilis, genital herpes,
AIDS
• Maternal diet and nutrition
• Emotional states and stress
• Maternal age
• Paternal factors
• Environmental hazards
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Slide 19
Prenatal Development
• Prenatal Care
– Prenatal care varies enormously, but usually involves a
defined schedule of visits for medical care that includes
screening for manageable conditions and treatable
diseases.
– Prenatal care programs often include comprehensive
educational, social, and nutritional services.
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Slide 20
Prenatal Development
Percentage of U.S. Women Using Timely
Prenatal Care: 1990 to 2001
• Refer to Figure 4.6
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Slide 21
Prenatal Development
• Cultural Beliefs About Pregnancy
– A woman’s behavior during pregnancy is often
determined by cultural beliefs.
• Normal Prenatal Development
– Most of the time, prenatal development does not go
awry and development occurs along the positive path
described (Lester, 2000).
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Slide 22
Review and Reflect:
Learning Goal 1
• Describe prenatal development
– Review
• What is the course of prenatal development?
• What are some of the main hazards to prenatal
development?
• What are some good prenatal care strategies?
• What are some cultural beliefs about pregnancy?
• Why is it important to take a positive approach to
prenatal development?
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Slide 23
Review and Reflect:
Learning Goal 1
– Reflect
• What can be done to convince women who are
pregnant not to smoke or drink? Consider the role of
health-care providers, the role of insurance
companies, and specific programs targeted at
women who are pregnant.
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Slide 24
Birth
• The Birth Process
– Stages of Birth
• First stage—Initially, uterine contractions are 15–20
minutes apart, last up to a minute, and cause the
cervix to dilate; in the late first stage, contractions
occur every 2–5 minutes and the cervix is dilated to
an opening of about 4 inches.
• Second stage—Birth of the infant.
• Third stage—Delivery of the placenta (afterbirth).
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Slide 25
Birth
• The Birth Process (continued)
– Childbirth Setting and Attendants
• While 99% of births in the U.S. take place in
hospitals, births at home are more common in many
other countries.
• Cultural norms differ with respect to the father’s
participation in the childbirth process.
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Slide 26
Birth
– Childbirth Setting and Attendants
(continued)
• Midwives are used by only 6% of women in the
U.S. (90% of U.S. births are attended by
physicians), although midwifery is the norm
throughout most of the rest of the world.
• Doula: A caregiver who provides continuous
physical, emotional, and educational support to the
mother before, during, and just after childbirth.
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Slide 27
Birth
• The Birth Process (continued)
– Methods of Childbirth
• Three kinds of drugs are used during labor:
– Analgesia to relieve pain
– Anesthesia to block sensation or to block
consciousness
» Epidural block
– Oxytocics to stimulate contractions
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Slide 28
Birth
– Methods of Childbirth (continued)
• Natural and Prepared Childbirth
– Natural childbirth: This method attempts to
reduce the mother’s pain by decreasing her fear
through education about childbirth and
relaxation techniques during delivery (developed
by Dick-Read).
– Prepared childbirth: This childbirth strategy is
similar to natural childbirth but includes a
special breathing technique to control pushing in
the final stages of labor and a more detailed
anatomy and physiology course (developed by
Ferdinand Lamaze).
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Slide 29
Birth
– Methods of Childbirth (continued)
• Cesarean Delivery
– Breech position: The baby’s position in the uterus
that causes the buttocks to be the first part to emerge
from the vagina and requires a cesarean delivery in
which the baby is removed from the mother’s uterus
through an incision made in her abdomen.
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Slide 30
Birth
• The Birth Process (continued)
– The Transition from Fetus to Newborn
• During contractions, oxygen supply to the fetus is
decreased
– If labor takes too long, anoxia (insufficient
supply of oxygen) can develop, which can cause
brain damage.
• Adrenaline and noradrenaline are secreted to protect
the fetus in the event of anoxia.
• Vernix caseosa: A protective skin grease that
protects the neonate against heat loss.
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Slide 31
Birth
• Assessing the Newborn
– Apgar Scale
• A widely used method to assess the health of
newborns at 1 and 5 minutes after birth. The Apgar
Scale evaluates infant heart rate, respiratory effort,
muscle tone, body color, and reflex irritability.
• Scale of 0, 1, or 2: Total score of 7–10 indicates
good condition, 5 indicates possible problems,
below 3 signals a life-threatening emergency.
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Slide 32
Birth
The Apgar Scale
• Refer to Figure 4.7
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Slide 33
Birth
• Assessing the Newborn (continued)
– Brazelton Neonatal Behavioral Assessment
Scale (NBAS)
• A test given 24 to 36 hours after birth to assess
newborns’ neurological development, reflexes, and
reactions to people; also used in research studies on
infant development.
• 27 items are organized in four categories:
physiological, motoric, state, and interaction.
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Slide 34
Birth
• Assessing the Newborn (continued)
– Neonatal Intensive Care Unit Network
Neurobehavioral Scale (NNNS)
• An offshoot of the NBAS to assess at-risk infants.
• Provides a more comprehensive analysis of the
newborn’s behavior, neurological and stress
responses, and regulatory capacities.
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Slide 35
Birth
• Low Birth Weight and Preterm Infants
– Low birth weight: An infant who weighs less than 5 1/2
pounds at birth.
• Very low birth weight: Under 3 pounds.
• Extremely low birth weight: Under 2 pounds.
– Preterm infant: An infant born 3 weeks or more before
the pregnancy has reached its full term.
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Slide 36
Birth
• Low Birth Weight and Preterm Infants
(continued)
– Small for Date Infant
• Also called a small for gestational age infant, this
infant’s birth weight is below normal when the
length of pregnancy is considered. A small for date
infant may be preterm or full-term.
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Slide 37
Birth
Preterm Births in the United States: 1982–
2002
• Refer to Figure 4.8
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Slide 38
Birth
• Low Birth Weight and Preterm Infants
(continued)
– Incidences and Causes of Low Birth Weight
• The U.S. rate of 7.6% is considerably higher than
that of many other developed countries (4–5%), but
the rate in poor countries can be as high as 50%.
• Causes: Mother’s poor health and nutrition, diseases
that impair fetal growth, cigarette smoking during
pregnancy, young age of mother, use of drugs.
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Slide 39
Birth
• Low Birth Weight (continued)
– Consequences of Low Birth Weight
• Most are normal and healthy.
• Low brain weight increases the likelihood of brain
injury.
• At-risk for lung or liver diseases.
• Increased risk for learning disability, attention
deficit hyperactivity disorder, and breathing
problems.
• Intensive enrichment programs improve short-term
outcomes.
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Slide 40
Birth
• Low Birth Weight (continued)
– Kangaroo Care and Massage
• Kangaroo care: A way of holding a preterm infant so
that there is skin-to-skin contact that improves
breathing, heart rate, temperature, sleep, and weight
gain and results in decreased crying, greater
alertness, and earlier hospital discharge.
• Massage: Tiffany Field has shown that massage
therapy lowers stress and improves emotionality,
sociability, soothability, weight gain, and earlier
discharge from hospital.
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Slide 41
Explorations in Child
Development
Weight Gain Comparison of Premature Infants
Who Were Massaged or Not Massaged
• Refer to Figure 4.9
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Slide 42
Review and Reflect: Learning
Goal 2
• Discuss the birth process
– Review
• What are the three stages of birth? What are some
different childbirth strategies? What is the transition
from fetus to newborn like for the infant?
• What are three measures of neonatal health and
responsiveness?
• What are the outcomes for children if they are born
preterm or with a low birth weight?
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Slide 43
Review and Reflect: Learning
Goal 2
– Reflect
• If you are a female, which birth strategy do you
prefer? Why? If you are a male, how involved
would you want to be in helping your partner
through pregnancy and the birth of your baby?
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Slide 44
The Postpartum Period
• What Is the Postpartum Period?
– The period after childbirth when the mother
adjusts, both physically and psychologically, to
the process of childbirth. This period lasts for
about 6 weeks or until her body has completed
its adjustments and returned to a nearly
prepregnant state.
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Slide 45
The Postpartum Period
• Physical Adjustments
– Initial fatigue can undermine the mother’s sense of
well-being and confidence.
– After delivery, a woman’s body undergoes sudden and
dramatic changes in hormone production.
– Involution is the process by which the uterus returns to
its prepregnant size 5 or 6 weeks after birth.
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Slide 46
The Postpartum Period
• Emotional and Psychological Adjustments
– “Baby Blues” and Postpartum Depression
• Signs that professional counseling is needed include:
– Excessive worrying
– Depression
– Extreme changes in appetite
– Crying spells
– Inability to sleep
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Slide 47
The Postpartum Period
– Postpartum Depression (continued)
• Postpartum depression: Strong feelings of
sadness, anxiety, or despair in new mothers that
make it difficult for them to carry out daily tasks.
• The role of hormonal changes in postpartum
depression has not yet been identified.
• Postpartum depression also affects the child.
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Slide 48
The Postpartum Period
• Emotional and Psychological Adjustments
– The Father’s Adjustment
• The baby comes first and gets all the attention
• Parents need to
– Set aside time for each other
– Become aware of the infant’s needs
– Develop a sensitive, comfortable relationship
with the baby
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Slide 49
The Postpartum Period
Percentage of U.S. Women Who Experience
Postpartum Blues and Postpartum Depression
• Refer to Figure 4.10
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Slide 50
The Postpartum Period
• Bonding
– The formation of a close connection, especially a
physical bond, between parents and their newborn in
the period shortly after birth.
– Rooming-in arrangements allow the baby to remain in
the mother’s room during most of the hospital stay to
increase bonding.
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Slide 51
Review and Reflect:
Learning Goal 3
• Explain the changes that take place in the
postpartum period
– Review
• What does the postpartum period involve? What
physical adjustments does the woman’s body make
in this period?
• What emotional and psychological adjustments
characterize the postpartum period?
• Is bonding critical for optimal development?
McGraw-Hill
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Slide 52
Review and Reflect:
Learning Goal 3
– Reflect
• If you are a female, what can you do to adjust
effectively in the postpartum period? If you are a
male, what can you do to help the mother adjust in
the postpartum period?
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Slide 53
Summary
• Prenatal development is divided into three periods:
germinal (conception until 10 to 14 days later),
embryonic (2 to 8 weeks after conception), and
fetal (2 months after conception until about 9
months, or when the infant is born).
• Teratology is the field that investigates the causes
of congenital (birth) defects.
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Slide 54
Summary
• Prenatal care varies extensively but usually
involves medical care services with a defined
schedule of visits.
• Specific actions in pregnancy are often determined
by cultural beliefs.
• Although things can and do go wrong during
pregnancy, most of the time pregnancy and
prenatal development go well.
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Slide 55
Summary
• Childbirth occurs in three stages:
– First: Contractions and dilation of cervix
– Second: Baby’s head moves through cervix; the baby is
born
– Third: Afterbirth
• Baby is prepared and capable of adapting to
handle the stress of birth, but anoxia (lack of
oxygen, especially if labor is prolonged) is a
potential hazard.
• Childbirth strategies vary around the world.
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Slide 56
Summary
• For many years, the Apgar Scale has been used to
assess the newborn’s health. The Brazelton
Neonatal Behavioral Assessment Scale examines
the newborn’s neurological development, reflexes,
and reactions to people.
• More recently the Neonatal Intensive Care Unit
Network Neurobehavioral Scale was created to
assess at-risk infants.
McGraw-Hill
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Slide 57
Summary
• Low birth weight infants weigh less than 5 1/2
pounds at birth and may be preterm or small for
date.
• Most low birth weight infants are normal and
healthy, but as a group they have more health and
developmental problem than other children.
• Kangaroo care and massage therapy are beneficial
for preterm infants.
McGraw-Hill
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Slide 58
Summary
• The postpartum period is the name given to the
period after childbirth or delivery.
• Physical adjustments in the postpartum period
include fatigue, involution (the process by which
the uterus returns to its prepregnant size 5 or 6
weeks after birth), hormonal changes, and
deciding when to resume sexual intercourse and
when to begin exercises to recover body contour
and strength.
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Slide 59
Summary
• Emotional fluctuation of the mother is common in
the postpartum period.
• Approximately 10% of U.S. women experience
postpartum depression, which involves such
strong feelings of sadness, anxiety, or despair that
new mothers have difficulty carrying out daily
tasks.
McGraw-Hill
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Slide 60
Summary
• Bonding is the formation of a close connection,
especially a physical bond, between parents and
the newborn shortly after birth.
McGraw-Hill
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