Santrock Life-span development 16th edition slides.

1. LIFE-SPAN DEVELOPMENT
Sixteenth Edition
Chapter 3
Prenatal
Development
and Birth
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prior written consent of McGraw-Hill Education.

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Chapter Outline
• Prenatal development
• Birth
• The postpartum period

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prior written consent of McGraw-Hill Education.
Prenatal Development
• The course of prenatal development
• Teratology and hazards to prenatal
development
• Prenatal care
• Normal prenatal development

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prior written consent of McGraw-Hill Education.
The Course of Prenatal Development
(1 of 4)
• Germinal period: Takes place in the first two
weeks after conception
– Includes:
 Creation of the zygote
 Continued cell division
 Attachment of the zygote to the uterine wall
– Blastocyst: Inner layer of cells that develops
into the embryo
– Trophoblast: Outer layer of cells that provides
nutrition and support for the embryo

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prior written consent of McGraw-Hill Education.
The Course of Prenatal Development
(2 of 4)
• Embryonic period: Occurs two to eight weeks
after conception
– Rate of cell differentiation intensifies and mass
of cells is now called embryo
 Three layers of cells - Endoderm, mesoderm,
ectoderm
– Support systems for the cells form and organs
appear
– Amnion: Contains a clear fluid in which the
developing embryo floats

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The Course of Prenatal Development
(3 of 4)
– Umbilical cord: Contains two arteries and one
vein, and connects the baby to the placenta
– Placenta: Disk-shaped group of tissues in which
small blood vessels from the mother and the
offspring intertwine but do not join
– Organogenesis: Organ formation that takes
place during the first two months of prenatal
development
• Fetal period: Period between two months after
conception and birth

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The Course of Prenatal Development
(4 of 4)
• Brain
– Neurons: Nerve cells, which handle
information processing at the cellular level in
the brain
– Important phases of the brain’s development
 Neural tube
o Failure of the neural tube to close may cause
anencephaly and spina bifida
 Neurogenesis - Generation of new neurons
 Neuronal migration - Cells moving outward from
their point of origin to their appropriate locations
 Neural connectivity

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Significant Developments in the
Germinal Period

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The Placenta and the Umbilical Cord

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The Three Trimesters of Prenatal
Development (1 of 6)
First trimester (first 3 months)
• Conception to 4 weeks
– Is less than 1/10 inch long
– Beginning development of
spinal cord, nervous system,
gastrointestinal system, heart,
and lungs
– Amniotic sac envelops the
preliminary tissues of entire
body
– Is called a "zygote"

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The Three Trimesters of Prenatal
Development (2 of 6)
• 8 weeks
– Is just over 1 inch long
– Face is forming with rudimentary eyes, ears, mouth;
and tooth buds
– Arms and legs are moving
– Brain is forming
– Fetal heartbeat is detect-able with ultrasound
– Is called an "embryo“
• 12 weeks
– Is about 3 inches long and weighs about 1 ounce
– Can move arms, legs, fingers, and toes
– Fingerprints are present
– Can smile, frown, suck, and swallow
– Sex is distinguishable
– Can urinate
– Is called a "fetus"

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The Three Trimesters of Prenatal
Development (3 of 6)
Second trimester (middle 3
months)
• 16 weeks
– Is about 6 inches long and
weighs about 4 to 7 ounces
– Heartbeat is strong
– Skin is thin, transparent
– Downy hair (lanugo) covers body
– Fingernails and toenails are
forming
– Has coordinated movements; is
able to roll over in amniotic fluid

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The Three Trimesters of Prenatal
Development (4 of 6)
• 20 weeks
– Is about 12 inches long and weighs close to 1 pound
– Heartbeat is audible with ordinary stethoscope
– Sucks thumb
– Hiccups
– Hair, eyelashes, eyebrows are present
• 24 weeks
– Is about 14 inches long and weighs 1 to 11/2 pounds
– Skin is wrinkled and covered with protective coating
(vernix caseosa)
– Eyes are open
– Waste matter is collected in bowel
– Has strong grip

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The Three Trimesters of Prenatal
Development (5 of 6)
Third trimester (last 3 months)
• 28 weeks
– Is about 16 inches long and
weighs about 3 pounds
– Is adding body fat
– Is very active
– Rudimentary breathing
movements are present

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The Three Trimesters of Prenatal
Development (6 of 6)
• 32 weeks
– Is 161/2 to 18 inches long and weighs 4 to 5 pounds
– Has periods of sleep and wakefulness
– Responds to sounds
– May assume the birth position
– Bones of head are soft and flexible
– Iron is being stored in liver
• 36 to 38 weeks
– Is 19 to 20 inches long and weighs 6 to 71/2 pounds
– Skin is less wrinkled
– Vernix caseosa is thick
– Lanugo is mostly gone
– Is less active
– Is gaining immunities from mother

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Teratology and Hazards to Prenatal
Development (1 of 5)
• Teratogen: Agent that causes a birth defect
• Teratology - Field of study that investigates
the causes of birth defects
• Teratogen influence
– Dose
– Genetic susceptibility
– Time of exposure

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Teratology and Hazards to Prenatal
Development (2 of 5)
• Prescription drugs that can function as
teratogens include:
– Antibiotics – Streptomycin and tetracycline
– Antidepressants
– Hormones – Progestin and synthetic estrogen
– Accutane – Acne medication
• Nonprescription drugs that can be harmful
include diet pills and high dosages of aspirin

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Teratology and Hazards to Prenatal
Development (3 of 5)
• Psychoactive drugs - Act on the nervous
system to alter states of consciousness,
modify perceptions, and change moods
– Caffeine
– Alcohol
 Fetal alcohol spectrum disorders: Appear in the
off spring of mothers who drink alcohol heavily
during pregnancy
– Nicotine, cocaine, methamphetamine,
marijuana, heroin

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Teratology and Hazards to Prenatal
Development (4 of 5)
• Incompatible blood types
– Incompatibility between the mother’s and
father’s blood types poses risk to prenatal
development
• Environmental hazards
– Radiation, toxic wastes, and other chemical
pollutants
• Maternal diseases
– Rubella and syphilis
– Genital herpes and AIDS

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Teratology and Hazards to Prenatal
Development (5 of 5)
• Other parental factors
– Maternal diet and nutrition
– Maternal age
– Emotional states and stress
– Paternal factors

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prior written consent of McGraw-Hill Education.
Teratogens and The Timing of Their
Effects on Prenatal Development

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Prenatal Care (1 of 2)
• Screening for manageable conditions and
treatable diseases
• Programs include educational, social, and
nutritional services
• Exercise during pregnancy:
– Helps prevent constipation
– Conditions the body
– Reduces excessive weight gain
– Is associated with a more positive mental state

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Prenatal Care (2 of 2)
• Centering Pregnancy - Relationship-centered
program which provides complete prenatal
care in a group setting
• Nurse Family Partnership - Home visits by
trained nurses beginning in the second or
third trimester of prenatal development

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Birth
• The birth process
• Assessing the newborn
• Preterm and low birth weight infants

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Birth Process (1 of 3)
• Stages of birth - Three stages
– 1st stage - Uterine contractions are 15 to 20
minutes apart and last up to 1 minute
 Longest Stage
– 2nd stage - Begins when the baby’s head
starts to move through the cervix and birth
canal
 Ends when the baby completely emerges from
the mother’s body
– 3rd stage
 Afterbirth: When the placenta, umbilical cord,
and other membranes are detached and
expelled

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Birth Process (2 of 3)
• In the United States, 98.6 percent of births
take place in hospitals
– Midwives
– Doula: Caregiver who provides continuous
physical, emotional, and educational support
for the mother before, during, and after
childbirth
• Methods of childbirth
– Medication
 Analgesia, anesthesia, and oxytocin

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Birth Process (3 of 3)
– Natural childbirth: Reduces the mother’s pain by
decreasing her fear through:
 Education about childbirth
 Relaxation techniques during delivery
– Prepared childbirth: Special breathing technique to
control pushing in the final stages of labor
 Provides detailed anatomy and physiology course
 Called Lamaze method
– Cesarean delivery: Surgical procedure in which the
baby is removed from the mother’s uterus through
an incision made in her abdomen
 Breech position: Baby’s position in the uterus that
causes the buttocks to be the first part to emerge
from the vagina

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Assessing the Newborn (1 of 2)
• Apgar scale: Assessing the health of
newborns at one and five minutes after birth
– Evaluates:
 Infant’s heart rate
 Respiratory effort
 Muscle tone
 Body color
 Reflex irritability

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Assessing the Newborn (2 of 2)
• Brazelton Neonatal Behavioral Assessment
Scale (NBAS):
– Used in the first month of life to assess the
newborn’s neurological development, reflexes,
and reactions to people and objects
• Neonatal Intensive Care Unit Neurobehavioral
Scale (NNNS)
– Assessment of the newborn’s behavior,
neurological and stress responses, and
regulatory capacities

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The Apgar Scale
Score 0 1 2
Heart rate Absent
Slow—less than
100 beats per
minute
Fast-100-140
beats per minute
Respiratory
effort
No breathing for
more than one
minute
Irregular and slow
Good breathing
with normal crying
Muscle tone Limp and flaccid
Weak, inactive, but
some flexion of
extremities
Strong, active
motion
Body color Blue and pale
Body pink, but
extremities blue
Entire body pink
Reflex
irritability
No response Grimace
Coughing,
sneezing and
crying
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Preterm and Low Birth Weight
Infants (1 of 2)
• Preterm and small for date infants
– Low birth weight infants: Weighs less than 5½
pounds at birth
– Preterm infants: Born before the completion of
37 weeks of gestation
– Small for date infants: Infants’ birth weights
are below normal when the length of
pregnancy is considered

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Preterm and Low Birth Weight
Infants (2 of 2)
• Consequences of preterm birth and low birth
weight
– More health and developmental problems than
normal birth weight infants
• Nurturing low birth weight and preterm
infants
– Kangaroo care: Involves skin-to-skin contact
– Massage therapy

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The Postpartum Period (1 of 2)
• Physical adjustments
• Emotional and psychological adjustments
– Postpartum depression: involves a major
depressive episode that typically occurs four
weeks after delivery
• Bonding

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The Postpartum Period (2 of 2)
• Period after childbirth that lasts until:
– Mother’s body has completed its adjustment
and has returned to a nearly pre-pregnant
state
• Adjustments needed are:
– Physical
– Emotional
– Psychological

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Physical Adjustments
• Fatigue
• Hormonal changes

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Emotional and Psychological
Adjustments
• Postpartum depression: Strong feelings of
sadness, anxiety, or despair
– Have trouble coping with daily tasks in the
postpartum period
– Treatment - Antidepressant drugs,
psychotherapy, and regular exercise

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Sleep Deprivation in Pregnant and
Postpartum Women

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Postpartum Blues and Postpartum
Depression Among U.S. Women

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Bonding
• Formation of a physical bond, between
parents and their newborn shortly after birth
• Rooming-in arrangement - Baby remains in
the mother’s room most of the time during its
hospital stay