Transcript File - Yesenia King

CONCEPTION,
PREGNANCY, AND
CHILDBIRTH
Chapter 11
Learning Objectives
• Conception
• Infertility
• Pregnancy
• Prenatal Development
• Childbirth
• The Postpartum Period
Conception
Union of a sperm cell and an ovum
• Zygote is a fertilized ovum
• Each ejaculate contains an average of 200 to
400 million sperm
• Ovum secretes a chemical that attracts sperm
• Fertilization normally occurs in a fallopian tube
• Ovum is surrounded by zona pellucida which
must be penetrated by sperm to fertilize it
• Sperm secrete the enzyme hyaluronidase,
which briefly thins zona pellucida, enabling
penetration
Conception
Union of a sperm cell and an ovum
•
•
•
•
•
•
Ova carry X sex chromosomes
Sperm carry either X or Y sex chromosomes
Girls are produced from union of 2 X
Boys are produced from union of an X and a Y
Y sperm appear to be faster swimmers
Male fetuses more likely lost in spontaneous
abortion, which helps balance the sexes
• Spontaneous abortion is the loss of pregnancy,
often in the first month, and sometimes before
the woman knows she’s pregnant
Conception
Optimizing Chances
• Ovum can be fertilized for 4-20 hours after
ovulation
• Sperm are most active within 48 hours after
ejaculation
• Ways to predict ovulation
• Basal body temperature (BBT) chart
• Analyzing urine or saliva for luteinizing
hormone
• Tracking vaginal mucus
• Coitus in the male-superior position
Conception
Selecting the Sex of Your Child
• Reasons to select
• Personal preference
• Family balancing
• Avoidance of sex-linked diseases
• Folklore provides many techniques
• Selective abortion
• Infanticide
• Sperm-separation procedures
• Pre-implantation genetic diagnosis (PGD)
• Currently the most reliable sex-selection method
Critical Thinking
Sex selection raises
many moral and ethical
questions. Many people
wonder whether people
have the “right” to select
the sex of their children.
Where do you stand on
the issue? Why?
Infertility
Inability
to
conceive
a child
• Term usually not applied
until the failure has persisted
for more than a year
• Women over the age of 35
are advised to seek help
after 6 months of trying
• About 15% of American
couples experience infertility.
Infertility
• Low sperm count
• Irregularly shaped sperm
• Low sperm motility (selfpropulsion)
• Chronic diseases (diabetes,
infectious diseases)
• Injury to the testes
• Autoimmune response
(antibodies deactivate sperm)
• Pituitary imbalance and/or
thyroid disease
Male
Fertility
Problems
Infertility
• Microsurgery
• Artificial insemination
• Introduction of sperm into
the reproductive tract
through means other than
sexual intercourse
Male
infertility
solutions
include
Infertility
Female
Fertility
Problems
• Irregular ovulation, including
failure to ovulate (10-15%)
• Obstructions or malfunctions of
the reproductive tract, such as
blocked fallopian tubes
• Endometriosis
• Endometrial tissue is sloughed
off into the abdominal cavity
rather than out of the body
during menstruation
• Declining hormone levels
Infertility
• Fertility drugs
• Laparoscopy (for detection & treatment)
• In vitro fertilization (IVF)
• Mature ova are surgically removed
from an ovary and placed in a
laboratory dish along with sperm
• Gamete intrafallopian transfer (GIFT)
• Sperm and ova are inserted into a
fallopian tube to encourage
conception
• Zygote intrafallopian transfer (ZIFT)
• Ovum is fertilized in a laboratory dish
and then placed in a fallopian tube
Female
infertility
solutions
include
Infertility
Female
infertility
solutions
include
• Donor IVF
• Ovum is taken from one woman,
fertilized, and then injected into the
uterus or fallopian tube of another
woman
• Embryonic transfer
• Woman volunteer is artificially
inseminated by the male partner of the
intended mother
• Embryo is removed and inserted within
the uterus of the intended mother
• Intracytoplasmic sperm injection
• Single sperm is injected directly into an
ovum
Infertility
• Surrogate motherhood
• Woman is impregnated
through artificial
insemination with the sperm
of a prospective father
• Carries the embryo and
fetus to term
• Gives the child to the
prospective parents
• Adoption
Female
infertility
solutions
include
Pregnancy
Early Signs of Pregnancy
• Missing a period
• It is not a reliable indicator.
• Basal body temperature
remains high for about three
weeks after ovulation
Pregnancy
Early Effects of Pregnancy
• Tenderness of the breasts
• Morning sickness
• Nausea, aversions to specific foods, and
vomiting
• May occur throughout the day
• Usually subsides by about the twelfth week of
pregnancy
• May experience more fatigue and frequent
urination
Pregnancy
Miscarriage
• Spontaneous abortion
• Causes include chromosomal
defects in the embryo or fetus
• More common in older
pregnant women
Pregnancy
Sex During Pregnancy
• Given a normal pregnancy, coitus is safe
throughout pregnancy until the start of
labor
• A pregnant woman’s interest in sex may
vary
• Tends to be higher during the second
trimester compared to the first and third
Pregnancy
Psychological Changes During
Pregnancy
• Reflect desire to be pregnant, her
physical changes, and her attitudes
toward these changes
• May also depend on the trimester of
pregnancy
• Men, like women, respond differently to
pregnancy
Prenatal Development
Calculate delivery date by using Naegele’s rule
Use date of first day of the last menstrual period
Add 7 days
Subtract 3 months
Add 1 year
Prenatal Development
Figure 11.3. The ovarian cycle, conception, and the early days of the germinal stage (p. 306).
Stages of Prenatal Development
Germinal
stage
First two weeks of pregnancy
Period before implantation in the
uterus
Also called the period of the ovum
Blastocyst
Embryo is a sphere of cells
surrounding a cavity of fluid
Embryonic disk is a
platelike inner part of
the blastocyst
Differentiates into the
ectoderm, mesoderm, and
endoderm of the embryo
Trophoblast is the
outer part of the
blastocyst
Develops into the amniotic
sac, placenta, and umbilical
cord
Stages of Prenatal Development
Embryonic
stage
Lasts from implantation through the
eighth week
Differentiation of the major organ
systems occurs
Development
of the embryo
follows two
trends
Cephalocaudal –
from the head
downward
Proximodistal – from
the central axis of
the body outward
Stages of Prenatal Development
Ectoderm
• Outermost cell
layer of the
embryo from
which skin and
nervous system
develop
• Neural tube –
hollow area in
the blastocyst
from which the
nervous system
will develop
Endoderm
Mesoderm
• Inner layer
of the
embryo
from which
the lungs
and
digestive
system will
develop
• Central
layer of the
embryo
from which
the bones
and
muscles
develop
Stages of Prenatal Development
Amniotic sac
Placenta
• The sac containing
the embryo/fetus
• Amniotic fluid
• Suspends and
protects the
embryo/fetus
• Organ connected to
fetus by umbilical cord
• Relay station between
mother and embryo/
fetus; allows for the
exchange of nutrients
and wastes
• Secretes hormones
that
• preserve pregnancy
• stimulate uterine
contractions that
induce childbirth
• help prepare breasts
for breastfeeding
Stages of Prenatal Development
Figure 11.4. Human embryos and fetuses (p. 307).
Stages of Prenatal Development
Fetal
stage
Begins by the ninth week and continues until birth
Fetal movements can be felt
Age of viability is the age at which a fetus can
sustain independent life
During the
seventh month,
the fetus
typically turns
upside down in
the uterus
Cephalic
presentation
Emergence of the
baby head first
from the womb
If not, may be in
a breech
presentation
Can complicate
premature birth
Environmental Influences on Prenatal Development
Maternal diseases
and disorders
• Malnutrition
• Obesity
Mother’s diet
• Teratogens
• Environmental
influences or agents
that can damage an
embryo or fetus
• Critical periods of
vulnerability
• When embryo or
fetus is vulnerable
to the effects of a
teratogen
Environmental Influences on Prenatal Development
Figure 11.5. Critical periods (p. 310).
Prenatal Development
Rubella (German
measles)
• Viral infection that can
cause mental
retardation and heart
disease in an embryo
Syphilis
• Sexually transmitted
disease caused by a
bacterial infection
• May cause
miscarriage or stillbirth
or be passed along to
the child in the form of
congenital syphilis
Toxemia
• Life-threatening
condition
characterized by high
blood pressure
HIV/Acquired
immunodeficiency
syndrome (AIDS)
• Destroys white blood
cells in the immune
system
• Majority of babies born
to infected mothers do
not become infected
themselves
Ectopic pregnancy
• Fertilized ovum
becomes implanted
someplace other than
the uterus
Prenatal Development
Rh incompatibility
• Antibodies
produced by a
pregnant
woman are
transmitted to
the fetus and
may cause
brain damage
or death
Vitamins
(high doses)
Drugs taken
by the mother
(and the
father)
• OTC
• Prescription
Narcotics
Hormones
• Diethylstilbestrol (DES)
• An estrogen that was once given to
women at risk for miscarriage to help
maintain pregnancy
• Suspected of causing cervical and
testicular cancer in some children
whose mothers used it when
pregnant
Tranquilizers
and sedatives
Marijuana
Cigarette smoking
• Increases risk of low birth weight, early infant
mortality, and intellectual impairments
Alcohol
• Fetal
alcohol
syndrome
(FAS)
X-rays
Prenatal Development
Averting
chromosomal
and genetic
abnormalities
• Genetic counseling
• Chorionic villus
sampling (10
weeks)
• Amniocentesis (4
months)
• Ultrasound
• Parental blood tests
• Test of fetal DNA
Childbirth
Lightening
Braxton-Hicks
contractions
Prostaglandins
Oxytocin
Baby’s head
drops into
the pelvis,
usually early
in 9th month
So-called
false labor
contractions
that are
relatively
painless
Uterine
hormones
that
stimulate
uterine
contractions
Pituitary
hormone
that
stimulates
uterine
contractions
Stages of Childbirth
First
stage
• Uterine contractions efface and dilate the
cervix
• 4 inches (10 cm)
• Transition
• Process during which the cervix becomes
nearly fully dilated and the head of the
fetus begins to move into the birth canal
• May last from a couple of hours to more
than a day during a first pregnancy and is
usually shorter in subsequent births
Stages of Childbirth
Second
stage
• Shorter than first stage
• Begins when cervix is fully dilated and
baby begins to move into the vagina
• Episiotomy may be performed
• Surgical incision in the perineum that
widens the birth canal, preventing
random tearing during childbirth
• Ends with birth of baby
Stages of Childbirth
Third
stage
In the new
world
• Placenta is expelled
• Once baby is breathing
adequately umbilical cord
is cut
Stages of Childbirth
Figure 11.7. The stages of childbirth (p. 319).
Methods of Childbirth
Anesthetized childbirth
• General anesthesia
• The use of drugs to put people to sleep and
eliminate pain
• May prolong labor
• They cross placental barrier and lower newborn’s
responsiveness
• Local anesthesia
• Eliminates pain in a specific area of the body
• Decreases newborn’s responsiveness
• Little evidence that medicated childbirth has
serious, long-term consequences
Figure 11.7. The stages of childbirth (p. 319).
Methods of Childbirth
Prepared childbirth: Lamaze method
• Women are taught to reduce pain by
thinking of pleasant images or engaging in
breathing and relaxation exercises
• Women attend classes and have a “coach”
to help them through the birthing process
• Anesthetics can be used, if needed
• Gives women a sense of control over
delivery process
Figure 11.7. The stages of childbirth (p. 319).
Methods of Childbirth
Cesarean section
• Fetus is delivered through a surgical incision in the abdomen
• Mostly without complications
• May cause urinary tract infections, inflammation of the uterine
wall, blood clots, or hemorrhaging
• Increases rate of pregnancy-related death (4x)
• Advised when normal delivery is difficult or is threatening the
health or life of mother or child
• Baby is in breech (feet downward) or transverse position
(crosswise birth position), large, mother is infected with HIV or
herpes, mother is tired
• Today, about 29% of births are by C-section.
• Some view this number as too high
• Can deliver subsequent
babies vaginally
Figure 11.7. The stages of childbirth (p. 319).
Birth Problems
Anoxia: Oxygen
deprivation
• Can result in brain damage and mental
retardation
• If prolonged, can result in cerebral palsy and
death
• Occurs due to constriction of the umbilical cord
Preterm and
low-birth weight
children
• Born before 37 weeks of gestation
• A weight of less than 5 pounds
• Respiratory distress syndrome
• Cluster of breathing problems, responsible for
many neonatal deaths
• Usually require monitoring and extra care
Stillbirth
• Baby is born dead
• Connected to fetal abnormalities, infection,
maternal medical conditions, and pregnancy
complications
• Most cases have no clear cause
Postpartum Period
Maternal Depression
• Baby Blues
• Statistically normal
• Lasts for about 10 days and does not impair functioning
Postpartum Period
Maternal Depression
• Postpartum Depression
• Affects 1 in 5 to 10 women
• Persistent and severe mood changes during the postpartum period,
involving feelings of despair and apathy and characterized by changes in
appetite and sleep, low self-esteem, and difficulty concentrating
• May result from interaction of biological and psychological factors
• Begins 4 weeks post delivery and may linger for weeks or months
Postpartum Period
Breastfeeding
vs. BottleFeeding
• About three in five women in the U.S.
breastfeed
• It is recommended that women
breastfeed for a year or more
• It reduces the general risk of infections
and allergies
• Prolactin
• A pituitary hormone that stimulates milk
production
• Lactation
• Production of milk by the mammary
glands
Postpartum Period
• Lochia
• Reddish vaginal discharge that may
persist for a month after delivery
• A non-nursing mother does not resume
menstruation until 2 to 3 months
postpartum
• Ovulation typically precedes
menstruation
Resumption
of Ovulation
and
Menstruation
• Obstetricians usually advise a 6-week
waiting period
Resumption
of Sexual
Activity