Prenatal Development and the Newborn period Flashcards
The Code of Life
Genes: deoxyribonucleic acid
molecule (DNA)
Chromosomes: Rod-shaped DNA
portions in 23 pairs
Contain genetic
blueprint for individuals
Replicate through
mitosis
Conception
Union of two gametes(sex
cells): egg and sperm
Each gamete contains half of the
genetic material found in other
cells (23 chromosomes)
*Zygote = fertilized egg (46
chromosomes)
*Timing of gamete creation
different for males and females!
The Blastocyst
By 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
Inner cell mass eventually becomes
embryo
Developmental Processes Cell Division
From Zygote to Blastocyst to Embryo to Fetus
Cell Division Begins ~12 hours after
fertilization
Cell Migration
Cell differentiation
Apoptosis (cell death)
Stage 1: Germinal Stage
(fertilization to 2 weeks)
Fertilized egg becomes
blastocyst at day 4 (a hollow
sphere of cells with bulge of
inner cell mass)
Travels to and implants in
uterus
Characterized by rapid and
methodical cell division
Stage where identical twins
usually originate
Stage 2: Embryonic Stage
(2-8 weeks)
Development of major organs and basic
anatomy
*After implantation, the inner
cell mass becomes the
embryo and the rest of the
cells develop into its support
system.
The Embryo
Neural tube =U-shaped groove formed
from top layer of differentiated cells in
embryo
Eventually becomes
brain and the spinal cord
The Embryo Support System
Placenta: permits the exchange of materials between the bloodstream of the fetus and that of the mother
Umbilical cord:
contains blood vessels
that travel between the placenta
and developing organism
*Amniotic Sac: Protective Buffer
Stage 3: Fetal Stage
(9 weeks - birth)
Formally starts when differentiation of major organs has occurred (organism now called fetus)
Characterized by rapid development
Organs more differentiated and begin working
Interconnections between body parts become more complex and integrated
By 20 weeks, facial expressions are present!
Cephalocaudal Development
(head to toe)
changes in size of head
relative to body
Fetal Behavior
By 12 weeks after gestation,
most of the movements that
will be present at birth have
appeared
*Prenatal to postnatal continuity!!!
(Important!)
*Movement in utero = practice for
external functions (hiccups, swallowing, moving, waking, fetal ‘breathing’)
Fetal Sensory Experience
Not many visual experiences - REM sleep
Lots of opportunity for tactile stimulation
Fetuses have a preference for certain
tastes before birth (i.e., saccharin)
These preferences last until childhood;
more pronounced in breast-fed infants
They prefer smells associated with foods
that the mother has eaten.
Fetal Learning
DeCasper & Spence (1986):
Newborn infants recognize rhymes
and stories presented before birth
*Newborns also prefer familiar smells, tastes, and sound
patterns from womb
‐amniotic fluid
‐long-lasting taste preferences
Protection of Developing Child
Placental membrane= barrier against some
(not all!) toxins/infectious agents
Amniotic sac= membrane filled with fluid in
which infant floats, provides protective buffer
Teratogens
Environmental agents that have potential to cause
harm during prenatal development
Timing is crucial factor in severity of effects of these potentially harmful agents
Many agents cause damage only if
exposure occurs during a sensitive period in
development
Famous Teratogens:
Thalidomide
Marketed from 1957-1961
Goal was to cure morning sickness
Big issue: Limb abnormalities in children; some
deaths
Some Environmental Hazards
to Fetus or Newborn
Drugs
Antidepressants
Opioids (Vicodin, Percocet, Oxycodone, Fentanyl, heroin)
Marijuana
Nicotine
Cigarette smoking
Secondhand smoke
E-cigarettes
Alcohol
Environmental pollutants
Toxic metals, synthetic hormones, plastic ingredients,
pesticides, herbicides
Air and water pollution
Lead (dose–response relationship)
Fetal alcohol spectrum
disorder (FASD)
when a mother’s alcohol consumption
during pregnancy affects the
fetus; can include facial
deformities, intellectual
disabilities, attention
problems, hyperactivity, and
other defects
Maternal Factors
Age, nutrition, disease, and stress-level of mother have
impact on prenatal development
Infants born to girls 15 years or younger = 3 to 4 times
more likely to die before first birthday than those whose
mothers are in 20s
Inadequate supply of
specific nutrients/vitamins
(e.g., folic acid) can have
dramatic consequences
(e.g., growth of the fetal brain)
Variety of diseases including
sexually transmitted diseases
present hazards to the fetus
Father’s Prenatal Influence
Relatively little research
Tobacco use
Drug use
Alcohol use
Treatment of mother
AGE!
What is it like to be born?
Newborn is squeezed very tightly during birth
* Forces liquid out of lungs
* Changes head shape
Anoxia – oxygen deprivation
* Consequence of normal birth process
* Prolonged anoxia can lead to brain damage
State of Arousal
Response to distress
A study found that quick response to crying results in
less crying several months later.
Another study found that ignoring crying during the
first 9 weeks reduced crying during the next 9 weeks.
Colic:excessive, inconsolable crying by a
young infant for no apparent reason
1 in 10 U.S. infants; typically ends around 3 months
No long-term effects
Outcomes at Birth
Birth weight
Average newborn: 7½ pounds
Low birth weight (LBW):less than 5½ pounds
High level of medical complications; high rates of
neurosensory deficits, frequent illnesses, lower IQ scores
Very low birth weight (VLBW):less than 3.3 pounds
Premature (preterm) babies: born at 37 weeks
after conception; small for gestational age
Increase in multiple births; infertility treatment
Outcomes at Birth
Long-term outcomes
Comparison statistics may confound SES with birth-
weight status.
Negative effects of birth status gradually diminish for
majority of LBW infants.
Special services and additional support may be
important.
Intervention factors
Kangaroo care
Breast milk
CCC: cuddled, caressed, and carried
Educational programs
Infant Mortality
Infant mortality
Death during the first year after birth
In the United States, in 2016: 5.87 deaths
per 1000 births
Relatively rare event in the Western
industrialized world
However, rates in the United States are
among the highest in the “first world”…
Poverty and lack of health insurance are
associated with high rates of infant mortality
