Download Psy 251 Chapter 4 - Donna Vandergrift

Chapter 4
Pregnancy and
Prenatal
Development
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prior written consent of McGraw-Hill Education.
Table - 4.1 Early Signs and
Symptoms of Pregnancy
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Prenatal Development
 Cephalocaudal principle: Development proceeds in a
head-to-tail direction.
 Upper parts of the body develop before lower parts of
the trunk.
 Proximodistal principle: Development proceeds from
within to without.
 Parts of the body near the center develop before the
extremities.
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Prenatal Development
 Gestation: Period of development between conception
and birth.
 Gestational age: Age of an unborn baby, usually dated
from the first day of an expectant mother’s last
menstrual cycle.
 Takes place in three stages:
 Germinal, embryonic, and fetal
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Germinal Stage
 First 2 weeks of prenatal development
 Characterized by:
 Rapid cell division
 Increasing complexity and differentiation
 Implantation in the wall of the uterus
 Implantation: Attachment of the blastocyst to the uterine
wall, occurring at between day 6 and 10.
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Figure 4.1 - Early Development of a
Human Embryo
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Embryonic Stage
 Characterized by rapid growth and development of
major body systems and organs.
 From about 2 to 8 weeks
 Organogenesis: Process in which the organs and major
body systems develop rapidly.
 Respiratory, digestive, and nervous
 Severely defective embryos usually do not survive
beyond the first trimester of pregnancy.
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Embryonic Stage
 Spontaneous abortion: Natural expulsion from the
uterus of a embryo that cannot survive outside the
womb.
 Factors that may cause miscarriages
 Abnormal pregnancies
 Chromosomal abnormalities
 Smoking
 Drinking alcohol, and drug use
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Figure 4.2 - The Developing Embryo
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Figure 4.3 - Organogenesis
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Fetal Stage
 Final stage of prenatal development, 8 weeks to birth.
 Characterized by increased differentiation of body
parts and greatly enlarged body size.
 Fetus adds a layer of fat in preparation for birth.
 Ultrasound: Prenatal medical procedure using highfrequency sound waves to detect the outline of a fetus
and its movements.
 Determines if a pregnancy is progressing normally.
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Maternal Factors
 Prenatal environment is the mother’s body.
 Everything that affects the mother’s well-being may
alter her unborn child’s environment and influence its
growth and health.
 Teratogen: Environmental agent that can interfere with
normal prenatal development and cause
developmental abnormalities.
 Virus, a drug, or radiation
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Nutrition and Maternal Weight
 Pregnant women typically need 300 to 500 additional
calories a day, including extra protein.
 Gaining too much weight leads to the risk of having a
large baby that needs to be delivered by induced labor
or cesarean section.
 Critical to include folic acid or folate in a pregnant
woman’s diet.
 Vitamin D deficiency may increase the risk of a child’s
developing multiple sclerosis later in life.
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Physical Activity and
Strenuous Work
 Moderate exercise does not seem to endanger the
fetuses of healthy women.
 Pregnant women should not push themselves and raise
their heart rate above 150.
 Regular exercise prevents constipation and improves
respiration, circulation, muscle tone, and skin elasticity.
 Greater risk of premature birth
 Strenuous working conditions, occupational fatigue, and
long working hours
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Drug Intake
 Medical drugs - No medication should be prescribed
for a pregnant or breast-feeding woman unless it is
essential for her health or her child’s.
 Alcohol
 Fetal alcohol syndrome (FAS): Combination of mental,
motor, and developmental abnormalities affecting the
offspring of some women who drink heavily during
pregnancy.
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Drug Intake
 Nicotine - Maternal smoking has been identified as the
single most important factor in low birth weight in
developed countries.
 Caffeine - Four or more cups of coffee a day during
pregnancy is related to increased risk of sudden death
in infancy.
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Drug Intake
 Marijuana and cocaine - Lead to:
 Birth defects
 Low birth weight
 Withdrawal-like symptoms at birth
 Increased risk of attention disorders and learning
problems later in life
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Maternal Illness
 Acquired immune deficiency syndrome (AIDS):
 Viral disease that undermines effective functioning of
the immune system.
 Perinatal transmission - Virus may cross over to the
fetus’ bloodstream through the placenta.
 During pregnancy, labor, or delivery or, after birth,
through breast milk
 Offspring of mothers with diabetes likely to develop a
wide range of birth defects.
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Maternal Illness
 Infections
 Toxoplasmosis - Infection caused by a parasite harbored
in the bodies of cattle, sheep, and pigs and in the
intestinal tracts of cats.
 Typically produces either no symptoms or symptoms like
those of the common cold.
 Thyroid deficiency
 Rubella - Almost certain to cause deafness and heart
defects in a baby if contracted by the mother.
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Maternal Anxiety and Stress
 Some tension and worry during pregnancy are normal
and do not necessarily increase risks of birth
complications such as low birth weight.
 Moderate maternal anxiety may even spur organization
of the developing brain.
 Unusual maternal stress may have harmful effects on
the unborn child.
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Maternal Age and Outside
Environmental Hazards
 Maternal age
 Chance of miscarriage or stillbirth rises with maternal
age.
 Outside environmental hazards
 Air pollution
 Chemicals
 Radiation
 Extreme heat and humidity
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Paternal Factors
Men’s exposure to
the following may
result in abnormal or
poor quality sperm:
Lead
Marijuana or
tobacco smoke
Large amounts of
alcohol or
radiation
DES
Pesticides or high
ozone levels
Men who smoke
have an increased
likelihood of
transmitting genetic
abnormalities.
Pregnant women’s
exposure to the
father’s secondhand
smoke has been
linked with:
Older fathers may
be a significant
source of birth
defects due to
damaged or
deteriorated sperm.
Low birth weight
Infant respiratory
infections
Sudden infant
death
Cancer in
childhood and
adulthood
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Table 4.3 – Teratogen Effects
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Disparities in Prenatal Care
 Increasing number of multiple births with heightened
risk of death within the first year
 Early births
 Benefits of prenatal care are not evenly distributed
 Ethnic disparity in fetal and postbirth mortality
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Need for Preconception Care
 Research-based guidelines for preconception care for
all women of childbearing age
 Physical examinations and the taking of medical and
family histories
 Vaccinations for rubella and hepatitis B
 Risk screening for genetic disorders and infectious
diseases such as STDs
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Need for Preconception Care
 Counseling women to:
 Avoid smoking and alcohol
 Maintain a healthy body weight
 Take folic acid supplements
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prior written consent of McGraw-Hill Education.
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