Transcript Ch. 3

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The Prenatal Period, Birth,
and the Newborn
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Prenatal Development
• Conception marks the beginning of prenatal
development.
– The transformative process in which the fertilized
ovum, known as a zygote, progresses through
several periods of development, finally emerging
from the womb as a neonate.
– The zygote contains 46 chromosomes, half from
the ovum and half from the sperm.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Figure 3.1: Female Reproductive System
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Prenatal Development
• Germinal Period (First Two Weeks after
Conception)
– During the germinal period, also known as the
period of the zygote, the zygote begins cell
division and travels down the fallopian tube
toward the uterus.
– The process of duplication is called cleavage and it
continues at a rapid pace.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Figure 3.2: Germinal Period
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Prenatal Development
• Ethical and Policy Applications of Life Span
Development: Stem Cell Research
– Types of stem cells:
» Embryonic stem cells
» Adult stem cells
» Umbilical-cord stem cells
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Prenatal Development
• Ethical and Policy Applications of Life Span
Development: Stem Cell Research
– In 2001, a federal ban was instituted limiting
federal funding for embryonic stem cells to
research conducted with the limited number of
stem cells lines that currently existed.
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Prenatal Development
• Ethical and Policy Applications of Life Span
Development: Stem Cell Research
– In 2009, the ban was lifted. Restoring federal
funds ensures that stem cell research is
conducted within similar ethical guidelines and
protocols as research in other areas.
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Prenatal Development
• Germinal Period (First Two Weeks after
Conception)
– Cell differentiation begins roughly 72 hours after
fertilization when the organism consists of about 1632 cells.
– By 4 days the organism consists of about 60-70 cells
formed into a hollow ball called a blastocyst, a fluidfilled sphere with cells forming a protective circle
around an inner cluster of cells from which the
embryo will develop.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Prenatal Development
• Germinal Period (First Two Weeks after
Conception)
– Implantation begins at about day 6 and is
complete by about day 11.
– By the end of the second week, the outer layer of
the blastocyst begins to develop into part of the
placenta, the principal organ of exchange between
the mother and developing organism.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Prenatal Development
• Embryonic Period (Third to Eighth Week after
Conception)
– By the third week after conception, the embryo
begins a period of structural development during
which the most rapid developments of the
prenatal period take place.
– All of the organs and major body systems form
during the embryonic period.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Prenatal Development
• Embryonic Period (Third to Eighth Week after
Conception)
– The mass of cells composing the embryonic disk
develops into layers:
• Ectoderm: upper layer
• Endoderm: lower layer
• Mesoderm: middle layer
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Prenatal Development
• Embryonic Period (Third to Eighth Week after
Conception)
– During the third week, the endoderm folds to
form the neural tube, which will develop into the
central nervous system.
– The brain develops rapidly and the head grows
faster than the other parts of the body during the
fifth week of development.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Prenatal Development
• Embryonic Period (Third to Eighth Week after
Conception)
– During the seventh week, a ridge called the
indifferent gonad appears; it will develop into the
male or female genitals, depending on the fetus’
sex chromosomes.
– The external genital organs are not apparent until
about 12 weeks.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Prenatal Development
• Embryonic Period (Third to Eighth Week after
Conception)
– At the end of the embryonic period, the embryo
weighs about 1/7 of an ounce and is one inch
long.
• All of the basic organs and body parts have formed in a
very rudimentary way.
• Serious defects that emerge during the embryonic
period often cause a miscarriage, or spontaneous
abortion.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Prenatal Development
• Fetal Period (Ninth Week to Birth)
– The fetal period is marked by the appearance of
bone.
– Between 17 to 20 weeks, the mother can feel the
fetus move.
– The first hair to appear is lanugo, a fine down-like
hair that covers the fetus’s body.
– The skin is covered with a greasy material called
the vernix caseosa, which protects the fetal skin.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Prenatal Development
• Fetal Period (Ninth Week to Birth)
– Body proportions become more like those of a
newborn infant.
– During the last three months of pregnancy, the
fetal body typically gains over 5 pounds and grows
7 inches.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Prenatal Development
• Fetal Period (Ninth Week to Birth)
– The age of viability—the age at which advanced
medical care permits a preterm newborn to
survive outside the womb—begins at about 22
weeks after conception.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Environmental Influences
on Prenatal Development
• Principles of Teratology
– A teratogen is an agent that causes damage to
prenatal development, producing a birth defect.
– The field of teratology attempts to find the causes
of birth defects so that they may be avoided.
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Environmental Influences
on Prenatal Development
• Principles of Teratology
1. There are critical periods during prenatal
development in which an embryo is more
susceptible to damage from exposure to
teratogens.
2. There are individual differences in susceptibility
to particular teratogens.
3. The amount of exposure (i.e., dose level) to a
teratogen influences its effects.
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Environmental Influences
on Prenatal Development
• Principles of Teratology
4. Teratogens show complicated effects on
development.
5. Some teratogens have subtle effects that result
in developmental delays that are not obvious at
birth.
6. Some teratogens display sleeper effects, effects
that are not visible until many years later.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Figure 3.3: Sensitive Periods
in Prenatal Development
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Table 3.1: Hazards to Prenatal Development
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Environmental Influences on Prenatal
Development
• Types of Teratogens
– Maternal Illness
• Illness can have devastating consequences for the
developing fetus.
»
»
»
»
Rubella (German Measles)
Chicken Pox
Mumps
Sexually Transmitted Infections
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Environmental Influences
on Prenatal Development
• Lives In Context: HIV Infection in Newborns
– Mother-to-child transmission of HIV has
decreased as a result of cesarean delivery, as well
as anti-HIV drugs to the mother and newborn.
– Worldwide, mother-to-child HIV transmission
remains a serious issue.
– Globally, breastfeeding accounts for 30 to 50% of HIV
transmission in newborns.
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Environmental Influences
on Prenatal Development
• Lives In Context: HIV Infection in Newborns
– Cultural, economic, and hygienic reasons often
prevent mothers in developing nations from
seeking alternatives to breastfeeding.
– 20% to 30% of neonates with HIV develop AIDS
during the first year of life and most die in infancy.
– Growth stunting, chronic infections, and
developmental delays are common among HIVinfected children.
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Environmental Influences
on Prenatal Development
• Prescription and Nonprescription Drugs
– Prescription teratogens: Antibiotics, certain
hormones, anticoagulants, anticonvulsants, and
some acne drugs.
– Nonprescription drugs, such as diet pills and cold
medicine, can also cause harm.
– Research findings on the teratogenic effects of
aspirin and caffeine are mixed.
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Environmental Influences
on Prenatal Development
• Alcohol
– An estimated 14% to nearly 30% of pregnant women
report consuming alcohol during their pregnancies.
– Alcohol abuse during pregnancy has been identified as
the leading cause of developmental disabilities
– Fetal alcohol spectrum disorders refer to the
continuum of effects of exposure to alcohol, which
vary with the timing and amount of exposure.
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Environmental Influences
on Prenatal Development
• Alcohol
– At the extreme end of the spectrum is fetal alcohol
syndrome (FAS), a cluster of defects appearing after
heavy prenatal exposure to alcohol that is detected in
2 to 7 infants per 1000 births.
– Moderate alcohol consumption (7 to 14 drinks per
week) is associated with fetal alcohol spectrum effects
known as partial fetal alcohol syndrome or fetal
alcohol effects.
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Environmental Influences on Prenatal
Development
• Cigarette Smoking
– Nicotine reduces the supply of oxygen and
nutrients available to the fetus, affecting growth
and development.
– Fetal deaths, premature births, and low birth
weight are associated with maternal smoking.
• Even babies born to light smokers (1 to 5 cigarettes per
day) show higher rates of low birth weight than do
babies born to nonsmokers.
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Environmental Influences
on Prenatal Development
• Marijuana
– The effects of marijuana on prenatal development
are not well understood.
– Evidence suggests that that marijuana use during
early pregnancy negatively affects fetal length and
birth weight; other research indicates attention
problems in adolescence.
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Environmental Influences
on Prenatal Development
• Other Drugs
– Prenatal exposure to cocaine is associated with
reduced birth weight, length and head
circumference and impaired motor performance
at birth.
– Heroin-exposed infants often show signs of
addiction and withdrawal symptoms including
tremors, irritability, abnormal crying, disturbed
sleep, and impaired motor control.
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Environmental Influences
on Prenatal Development
• Other Drugs
– The challenge of determining the effects of
prenatal exposure to cocaine and heroin is that
most of these infants were also exposed to other
substances, including tobacco, alcohol, and
marijuana, making it difficult to isolate the effect
of each drug on prenatal development.
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Environmental Influences
on Prenatal Development
• Environmental Hazards
– Prenatal development can be harmed by factors in
the environment, including chemicals, radiation,
and extremes of heat and humidity.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Environmental Influences
on Prenatal Development
• Ethical and Policy Applications of Life Span
Development: Maternal Drug Use While Pregnant
– In recent years, some states have sought to penalize
women for consuming illegal drugs while pregnant,
characterizing such behavior as child abuse and/or
neglect.
– About one half of states require physicians to test for
or report drug-exposed newborns to child protective
services or other agencies.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Environmental Influences
on Prenatal Development
• Ethical and Policy Applications of Life Span
Development: Maternal Drug Use While Pregnant
– In 2014, Tennessee became the only state to
specifically criminalize drug use during pregnancy,
charging substance-abusing pregnant women with
assault.
– In many instances, state supreme courts have
overruled the extension of child abuse laws to the
fetus.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Environmental Influences
on Prenatal Development
• Ethical and Policy Applications of Life Span
Development: Maternal Drug Use While
Pregnant
– Several agencies argue that criminal sanctions for
maternal drug use are ineffective as they
increase the risk of harm by discouraging
prenatal and postnatal care and undermining the
physician/patient relationship.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Environmental Influences
on Prenatal Development
• Parental Characteristics and Behaviors
– Nutrition
• Most women need to consume 2,200 to 2,900 calories
per day to sustain a pregnancy.
• Fetal malnutrition is associated with increased
susceptibility to complex diseases in postnatal life.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Environmental Influences
on Prenatal Development
• Parental Characteristics and Behaviors
– Nutrition
• Neural tube defects due to malnutrition:
» Spina bifida
» Anencephaly
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Environmental Influences
on Prenatal Development
• Parental Characteristics and Behaviors
– Emotional Well-Being
• Chronic and severe stress during pregnancy poses risks.
• Long-term exposure to stress hormones in utero is
associated with higher levels of stress hormones in
newborns, leading to negative developmental
consequences.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Environmental Influences
on Prenatal Development
• Parental Characteristics and Behaviors
– Maternal Age
• The pregnancy rates for women ages 35 to 39 nearly
doubled from 1985 to 2009, from 24 to 46.9 per 1,000
women; and the rate more than doubled for women
ages 40 to 44, from 4 to 10.1.
• Pregnancy and birth complications increase with age.
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Environmental Influences
on Prenatal Development
• Parental Characteristics and Behaviors
– Maternal Age
• The risk of having a child with Down syndrome
increases sharply with maternal age.
• However, the majority of women over age 35 give birth
to healthy infants.
» Older mothers tend to be healthier, and show lower rates of
alcohol consumption and cigarette smoking than do younger
mothers .
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Figure 3.4: Maternal Age and Risk of Down Syndrome
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Childbirth
– Childbirth progresses in three stages:
• Labor: Longest stage and typically lasts 8 to 14 hours
for a woman having her first child.
• Delivery: Begins when the cervix is fully dilated to 10
centimeters and the fetus’s head is positioned at the
opening of the cervix; can take from 30 minutes to an
hour.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Childbirth
– Childbirth progresses in three stages:
• Placenta separates from uterine wall and is expelled by
uterine contractions; takes place 5 to 15 minutes after
birth.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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VIDEO CASE
The Partner’s Role During Pregnancy and Birth
Pregnancy is an important event for relationships. How might it change a
couple’s relationship?
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Figure 3.5:
Stages of Labor
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Birth and the Newborn
• Childbirth
– Sometimes a vaginal birth is not possible because
of health or safety reasons for the mother or
fetus.
– A cesarean section, or C-section, is a surgical
procedure that removes the fetus from the uterus
through the abdomen.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Childbirth
– The average newborn is about 20 inches long and
weighs about 7 ½ pounds.
– Boys tend to be slightly longer and heavier than
girls.
– Newborns have distinctive features, including a
large head that is often long and misshapen from
passing through the birth canal.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Childbirth
– A healthy newborn is red-skinned and wrinkly at
birth; skin that is bluish in color indicates that the
newborn has experienced oxygen deprivation.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Cultural Influences on Development: Cultural
Differences in Childbirth
– Societies vary in their customs and perceptions of
childbirth, including the privacy afforded birth and
how newborns are integrated into the community.
– In the U.S., birth is a private event that usually
occurs in a hospital, attended by medical
personnel and one or two family members.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Cultural Influences on Development: Cultural
Differences in Childbirth
– In a small village in southern Italy, birth is a
community event. After birth, the midwife brings
the mother’s entire family to the mother’s room
and they take turns congratulating the mother
and baby.
– The Jahara of South America give birth under a
shelter in full view of everyone in the village.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Cultural Influences on Development: Cultural
Differences in Childbirth
– Childbirth is tied to social status in the BrongAhafo Region in Ghana.
– Many cultures conduct rites that they believe
protect newborns from evil and spirits.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Medical and Behavioral Assessment of Infants
– After birth, newborns are routinely screened with
the Apgar Scale, which provides a quick and easy
overall assessment of the baby’s immediate
health.
– The Apgar consists of five subtests: appearance,
pulse, grimace, activity, and respiration.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Table 3.2: Apgar Scale
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Birth and the Newborn
• Medical and Behavioral Assessment of Infants
– The Brazelton Neonatal Behavioral Assessment
Scale (NBAS) is the most common
neurobehavioral assessment administered to
newborns.
• It assesses the newborn’s neurological functioning,
including the strength of 20 inborn reflexes,
responsiveness to the physical and social environment,
and changes in state.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• The Newborn’s Perceptual Capacities
– Taste and smell are well-developed at birth.
– Visual capacities are more limited; newborn vision
is blurry and best at about 18 inches away.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• The Newborn’s Perceptual Capacities
– The most remarkable newborn capacities for
perception and learning are auditory in nature.
• The fetus responds to auditory stimulation as early as 23 to 25
weeks after conception.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Newborn States of Arousal
– Newborns display regular cycles of eating,
elimination, and states of arousal or degrees of
wakefulness.
– In a typical day, newborns move in and out of 6
infant states or levels of arousal.
– Most newborns spend about 70 percent of their
time sleeping and wake every 2 to 3 hours.
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Birth and the Newborn
• Newborn States of Arousal
– Newborns spend about half of their sleep time in
REM.
– REM is a way that the brain stimulates itself, which
is important for the growth of the central nervous
system.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Table 3.3: Newborn States of Arousal
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VIDEO CASE
Labor Preparation and Process
In this clip, doula Laura Erlich describes the process of labor and what
women and their partners can expect.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Infants at Risk: Low-Birthweight and Small-forDate Babies
– Prematurity and low birthweight are among the
leading causes of infant mortality, accounting for
35% of mortality cases in infancy.
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Birth and the Newborn
• Infants at Risk: Low-Birthweight and Small-forDate Babies
– Two types of low-birthweight infants:
• Preterm: born before their due date.
• Small for date: full-term but have experienced slow
growth and are smaller than expected for their
gestational age.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Infants at Risk: Low-Birthweight and Small-forDate Babies
– Infants are classified as low birthweight when they
weigh less than 2,500 grams (5 ½ pounds) at birth.
• Very low birthweight: weight less than 1,500 grams (3½
pounds)
• Extremely low birthweight: weight less than 750 grams
(1lb 10 oz.)
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Infants at Risk: Low-Birthweight and Small-forDate Babies
– About 8 percent of infants born in the United
States each year are low birthweight.
– Infants most at risk for developmental challenges,
handicaps, and difficulty surviving are those with
extremely low birthweight.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Lives in Context: Prenatal Care
– Prenatal care is critical for the health of both
mother and infant.
– About 16 percent of pregnant women in the U.S.
do not seek prenatal care until after the first
trimester; 4 percent seek prenatal care at the end
of pregnancy or not at all.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Lives in Context: Prenatal Care
– Barriers:
•
•
•
•
•
Lack of health insurance
Difficulty finding a doctor
Lack of transportation
Demands of caring for young children
Ambivalence about pregnancy
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Birth and the Newborn
• Lives in Context: Prenatal Care
– Barriers:
•
•
•
•
•
Depression
Lack of education
Lack of social support
Negative experiences in the health care system
Family crises
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Birth and the Newborn
• Lives in Context: Prenatal Care
– Ethnic and SES Differences
•
•
•
•
African American (75%)
Latino (77%)
Native American (70%)
Caucasian (89%)
– Latino paradox: Latino mothers, despite low rates
of prenatal care, experience low birthweight and
mortality rates below national averages.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Birth and the Newborn
• Infants at Risk: Low-Birthweight and Small-forDate Babies
– Small-for-date babies tend to have more serious
problems than preterm babies because their low
birthweight is a result of stunted growth and
development throughout pregnancy.
– Low-birthweight babies face physical, health,
cognitive, and socioemotional challenges.
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Birth and the Newborn
• Infants at Risk: Low-Birthweight and Small-forDate Babies
– Stable life circumstances and social support can
help low-birthweight babies overcome many
obstacles.
– Kangaroo care, which involves skin-to-skin
contact, is so effective that the majority of U.S.
hospitals offer it to preterm infants.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Figure 3.6: Very Low and Low Birth Weight
Rates, by Maternal Race/Ethnicity, 2012
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