Transcript Physiology of Pregnancy

Chapter 25
Health Promotion and Pregnancy
Mosby items and derived items © 2006, 2003, 1999, 1995, 1991 by Mosby, Inc.
Slide 1
Physiology of Pregnancy
• Fertilization
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During sexual intercourse, the sperm carried in the
ejaculatory semen of the male enters the vagina of the
female.
Through flagellation, the sperm travel through the
mucus of the cervical canal, enter the uterine
chamber, and move into the ampulla, the outer third of
the fallopian tube.
If the timing is such that an ovum has been produced
and is also within the ampulla of the tube, fertilization
may occur.
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Slide 2
Physiology of Pregnancy
• Fertilization (continued)
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Fertilization takes place when the sperm joins or fuses
with the ovum; this is called conception.
Once fertilization has occurred, the new cell is
referred to as a zygote or fertilized ovum.
At the moment of fertilization, the sex of the zygote
and all other genetic characteristics are determined
and they do not change.
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Slide 3
Physiology of Pregnancy
• Implantation
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The zygote moves through the uterine tube through
ciliary action and some irregular peristaltic activity.
 It requires about 3 or 4 days to enter the uterine
cavity.
 During this time, the zygote is in a phase of rapid cell
division called mitosis; further changes result in
formation of a structure called the morula.
 The morula develops into a blastocyst.
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Slide 4
Physiology of Pregnancy
• Implantation (continued)
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After the blastocyst is free in the uterine cavity for 1 or
2 days, the exposed cell walls of the blastocyst (called
the trophoblast) secrete enzymes that are able to
break down protein and penetrate cell membranes.
These enzymes allow the blastocyst to enter the
endometrium and implant.
The action of the enzymes normally stops short of the
myometrium but may cause slight bleeding; this is
called implantation bleeding.
The bleeding may confuse some women who think
they had a very light and short menstrual cycle.
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Slide 5
Physiology of Pregnancy
• Implantation (continued)
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The condition of the uterine lining is critical if
implantation of the zygote is to occur.
 Implantation usually occurs in the fundus of the uterus
on either the anterior or posterior surface.
 If uterine conditions are not suitable, it is unlikely that
implantation will occur.
 If the intrauterine vascular or hormonal conditions
cannot sustain the implanted embryo, a spontaneous
abortion will occur; usually during the first 8 weeks of
pregnancy.
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Slide 6
Physiology of Pregnancy
• Implantation (continued)
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Ectopic pregnancy, in which implantation occurs
outside of the uterine cavity, also poses serious
problems.
During the first few weeks after implantation, primary
villi appear; these villi are able to use maternal blood
vessels as a source of nourishment and oxygen for
the developing embryo.
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Slide 7
Physiology of Pregnancy
• Implantation (continued)
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It is also during these first few weeks that the first
stages of the chorionic villi occur.
Chorionic villi secrete human chorionic gonadotropin
(hCG), a hormone that stimulates the continued
production of progesterone and estrogen by the
corpus luteum; this is the reason that ovulation and
menstruation cease during pregnancy.
The chorionic villi become the fetal portion of the
placenta.
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Slide 8
Physiology of Pregnancy
• Embryonic/Fetal Development
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During this period, the fertilized ovum develops from
the two original cells into a many-celled organism.
The zygote develops two distinct cavities.
• Amniotic cavity: filled with amniotic fluid
• Yolk sac: supplies nourishment until implantation
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The mesoderm is located between the two cavities; it
gives rise to all types of muscle, connective tissue,
bone marrow, blood, lymphoid tissue, and all epithelial
tissue.
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Slide 9
Physiology of Pregnancy
• Embryonic/Fetal Development (continued)
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During the embryonic stage, the three primary cell
layers differentiate into tissue and layers that form the
placenta, embryonic membranes, and the embryo
itself.
A simple heart begins beating, and rudimentary forms
of all of the major organs and systems develop.
By the end of this stage, the embryo has acquired a
human appearance.
Starting with the ninth week, the embryo is referred to
as the fetus, and the fetal stage begins.
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Slide 10
Physiology of Pregnancy
• Embryonic/Fetal Physiology
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Placenta
• This disklike organ made up of about 20 sections called
cotyledons and is present only during pregnancy.
• At full term, the placenta looks like a large red disk with
a diameter of 6 to 10 inches and a thickness of 1 inch; it
weighs between 400 and 600 g (1 lb. to 1 lb. 5 oz).
• Uterine side: dark red with a rough surface
• Fetal side: smooth and shiny
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Slide 11
Physiology of Pregnancy
• Embryonic/Fetal Physiology (continued)
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Placenta
• It functions as an endocrine gland secreting hCG and
the steroidal hormones estrogen and progesterone,
which maintain pregnancy.
• It is the site of exchange of nutrients, oxygen, and
waste products between the fetus and the maternal
circulation.
• Placental barrier refers to the ability of the placenta to
block the transfer of certain substances.
• After delivery, the placenta is of no further use and is
expelled.
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Slide 12
Physiology of Pregnancy
• Embryonic/Fetal Physiology (continued)
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Fetal Membranes
• The amniotic sac is composed of two layers, both
originating in the zygote.
• The outer layer, the chorion, attaches to the fetal portion
of the placenta.
• The inner layer, the amnion, blends with the fetal
umbilical cord.
• These membranes appear to be very fragile, but in fact
they are strong enough to contain the fetus and
amniotic fluid even at full term.
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Slide 13
Physiology of Pregnancy
• Embryonic/Fetal Physiology (continued)
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Umbilical Cord
• The cord joins the embryo to the placenta; it originates
in the fetal portion of the placenta and is normally
attached near the center.
• The cord is usually 20 to 22 inches long and less than 1
inch in diameter at the time of delivery.
• The major part of the cord is a pale white, gelatinousmucoid substance called Wharton’s jelly; it prevents
compression of the blood vessels.
• There are two arteries (carry deoxygenated blood) and
one vein (carries oxygenated blood).
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Slide 14
Physiology of Pregnancy
• Embryonic/Fetal Physiology (continued)
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Amniotic Fluid
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Acts as a cushion against mechanical injury
Helps regulate fetal temperature
Allows the developing embryo/fetus room for growth.
Amount is about 30 ml at 10 weeks to 1 L at delivery
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Slide 15
Figure 25-3
(Courtesy of Marjorie Pyle, RNC, LifeCircle, Costa Mesa, California.)
Transabdominal amniocentesis.
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Slide 16
Physiology of Pregnancy
• Fetal Well-being
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A variety of technologic and assessment tools can be
used to evaluate fetal well-being.
These tools are used to evaluate maternal and fetal
health problems, fetal congenital anomalies, and fetal
growth and maturity.
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Ultrasonography
Maternal serum alpha-fetoprotein screening
Chorionic villus sampling
Nonstress test
Contraction stress test
Magnetic resonance imaging
Biophysical profile
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Slide 17
Maternal Physiology
• Hormonal Changes
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Estrogen and progesterone levels remain elevated for
the first 8 weeks of pregnancy as a result of hCG.
 After this time, the placenta takes over production and
maintains necessary levels.
 As long as these levels are high, follicle-stimulating
hormone (FSH), luteinizing hormone (LH), and
ovulation are suppressed, as is menstruation.
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Slide 18
Maternal Physiology
• Uterus
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The uterus enlarges during pregnancy as a result of
hormonal stimulus, increased vascularity, hyperplasia,
and hypertrophy.
The nonpregnant uterus is pear-shaped and weighs
about 50 g; by the third trimester, it is egg-shaped and
has increased weight to 1000 g.
In a nonpregnant state, it is a pelvic organ; when the
pregnancy reaches completion, the superior aspect of
the uterus will be located at the level of the xiphoid
process.
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Slide 19
Maternal Physiology
• Breasts
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There is hypertrophy of the mammary glandular tissue
and increased vascularization, pigmentation, size, and
prominence of nipples and areola.
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Changes are caused by hormonal stimulation.
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Slide 20
Maternal Physiology
• Maternity Cycle
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Antepartal or Prenatal Period
• Begins with conception and ends with the onset of labor
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Intrapartal or Perinatal Period
• Begins with the onset of labor and ends with delivery of
the placenta
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Postpartal Period
• Starts after the delivery of the placenta and lasts for
approximately 6 weeks or until the reproductive organs
return to the prepregnancy state
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Slide 21
Maternal Physiology
• Maternity Cycle (continued)
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Pregnancy spans 9 months, approximately 40 weeks
Divided into 3-month periods or trimesters.
• First trimester: weeks 1 through 13
• Second trimester: weeks 14 through 26
• Third trimester: weeks 27 through term gestation (38 to
40 weeks)
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Slide 22
Antepartal Assessment
• General Physical Assessment
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Ideally, the woman has been receiving regular medical
attention and is already known by the health care
provider.
Unfortunately, many people do not receive regular,
routine health care.
On the first visit, demographic data, such as age,
occupation, marital status, and insurance information,
are obtained; this helps the primary care practitioner
identify potential areas of concern.
A basic family and personal medical history is
obtained; it should include genetic diseases.
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Slide 23
Antepartal Assessment
• Genetic Counseling
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The most useful means of reducing the incidence of
genetic disorders is by preventing their transmission.
 With the accumulation of information about genetic
disorders, the probability of recurrence in any given
situation can be predicted with increased accuracy.
 A personal medical history is taken and a review of
systems is done.
 Lifestyle patterns are assessed.
 A basic physical examination is completed.
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Slide 24
Antepartal Assessment
• Obstetric Assessment
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Information about the woman’s gynecological,
menstrual, and obstetric history is obtained.
The number of pregnancies and their outcomes are
discussed.
• Gynecological Examination
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The gynecological examination is also performed at
this time.
The nurse is often called on to prepare the necessary
equipment and assist with this examination.
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Slide 25
Determination of Pregnancy
• Presumptive Signs
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Amenorrhea
Nausea and vomiting
Frequent urination
Breast changes
Changes in shape of the abdomen
Quickening
Skin changes
Chadwick’s sign
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Slide 26
Determination of Pregnancy
• Probable Signs
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Changes in the Reproductive Organs
• Hegar’s sign
• Goodell’s sign
• Ballottement
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Positive Pregnancy Test
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Slide 27
Figure 25-4
(From Wong, D.L., Perry, S.E., Hockenberry-Eaton, M.J. [2002]. Maternal-child nursing care. [2nd ed.].
St. Louis: Mosby.)
Hegar’s sign.
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Slide 28
Figure 25-5
(From Wong, D.L., Perry, S.E., Hockenberry-Eaton, M.J. [2002]. Maternal-child nursing care. [2nd ed.].
St. Louis: Mosby.)
Internal ballottement (18 weeks).
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Slide 29
Determination of Pregnancy
• Positive Signs
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Visualization
Fetal movement
Auscultation of fetal heartbeat
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Slide 30
Determination of Pregnancy
• Determination of the Estimated Date of Birth
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Normal human pregnancy, counting from the first day
of the last menstrual period, is about 280 days, 40
weeks, or 10 lunar months (slightly more than 9
calendar months).
Nägele’s rule
• Start with the first day of the woman’s last menstrual
period and count back 3 months; then add 7 days.
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Slide 31
Determination of Pregnancy
• Determination of the Estimated Date of Birth
(continued)
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If the woman does not keep a menstrual record, the
primary care provider must then rely on observations
such as quickening, estimation of fetal size by
palpation, or ultrasonic tests, all of which can be
unreliable.
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Slide 32
Determination of Pregnancy
• Obstetric Terminology
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Terms used to describe the number of times a woman
has been pregnant and given birth
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Gravida: indicates a pregnant women
Primigravida: one pregnancy
Nulligravida: no pregnancies
Multigravida: multiple pregnancies
Primipara: one birth
Nullipara: no births
Multipara: multiple births
Abortion: indicating loss of a fetus before the age of
viability
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Slide 33
Antepartal Care
• Health Promotion
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Pregnancy is a time in life when most women see the
importance of regular medical supervision and are
more willing to make changes in their habits than any
other time.
Once pregnancy is diagnosed, prenatal care is
instituted.
Early in pregnancy, the woman often begins to seek
information and make choices regarding how and
where she wishes to give birth.
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Slide 34
Antepartal Care
• Health Promotion (continued)
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Routine care during pregnancy begins with the initial
examination and history.
 Appointments are recommended once a month
through the seventh month, once every 2 weeks for
the next month, and then once every week until
delivery.
 Smoking and drinking alcoholic beverages during
pregnancy are contraindicated.
 Taking any medications or drugs during pregnancy,
including over-the-counter drugs, should be avoided.
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Slide 35
Antepartal Care
• Danger Signs During Pregnancy
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Visual disturbances
Headaches
Edema
Rapid weight gain
Pain
Signs of infection
Vaginal bleeding or drainage
Persistent vomiting
Muscular irritability or convulsions
Absence or decrease in fetal movement once felt
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Slide 36
Antepartal Care
• Nutritional/Metabolic Health Pattern
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Pica
• This is the craving and eating of substances that are not
normally considered edible.
• Substances such as clay or laundry starch are
commonly ingested.
• They are not toxic but may interfere with iron
absorption, resulting in anemia.
• Large amounts of clay may cause constipation.
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Slide 37
Antepartal Care
• Common Discomforts
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Excessive salivation
Nausea
Hyperemesis gravidarum
Pyrosis (heartburn)
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Slide 38
Antepartal Care
• Skin Changes
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Linea nigra: dark line midline of abdomen
Chloasma: the mask of pregnancy
Striae gravidarum: stretch marks
Spider nevi: dilated capillaries on the skin
Palmar erythema: reddened palms
Hirsutism: excessive body hair
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Slide 39
Antepartal Care
• Hygiene Practices
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Bathing and showering during pregnancy should
continue as part of routine hygiene.
 Increased perspiration is common, and good personal
hygiene is important to prevent body odor.
 Some primary care practitioners restrict tub baths in
the last month, because the cervix may have dilated.
 Most primary care practitioners recommend that
women avoid using hot tubs, sauna baths, and spas
during pregnancy.
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Slide 40
Antepartal Care
• Elimination
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Gastrointestinal System
• Slowing of intestinal peristalsis can result in abdominal
distention, flatulence, and constipation.
• Hemorrhoids can result from straining and because the
enlarged uterus puts pressure on the pelvic blood
vessels.
• Women with cholelithiasis may have problems as a
result of increased cholesterol level.
• Adequate fluid intake, dietary roughage, and exercise
may help reduce problems with constipation.
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Slide 41
Antepartal Care
• Elimination
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Urinary System
• Frequency of urination is a common complaint.
• The mother must excrete not only her own waste
products but also those of the fetus.
• Early in pregnancy, the enlarging uterus irritates the
bladder by putting pressure on it; this continues until the
uterus rises into the abdominal cavity.
• Later in pregnancy, when the presenting part descends
into the pelvis, the pressure and symptoms return.
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Slide 42
Antepartal Care
• Activity/Exercise
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Normal activity should continue throughout an
uncomplicated pregnancy.
Fatigue is a common complaint during pregnancy.
Changes in balance and posture occur as the fetus
increases in size; to compensate for the shifting
center of gravity, the lumbodorsal curve increases
(lordosis).
Hormonal influence on the pelvic bones, resulting in
joint relaxation, can lead to a waddling gait.
Leg cramps are a common occurrence.
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Slide 43
Antepartal Care
• Rest/Sleep
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Early in pregnancy, few changes in sleep patterns are
experienced.
As the size of the abdomen increases, it may become
increasingly difficult for the woman to find a position of
comfort.
The supine position is not recommended as a woman
approaches her due date; this may cause excessive
pressure on the aorta and vena cava and may result
in decreased circulation for the fetus.
Rest periods during the day with the feet elevated
should be encouraged.
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Slide 44
Figure 25-7
(From McKinney, E.S., James, S.R., Murray, S.S., Ashwill, J.W. [2005]. Maternal-child nursing. [2nd ed.].
Philadelphia: Saunders.)
During third trimester, pillows supporting abdomen and back provide
a comfortable position for rest.
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Slide 45
Antepartal Care
• Sexuality/Reproductive System
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Breast Changes
• Breast changes begin early in pregnancy; there may be
tingling and a feeling of fullness.
• Generally, the breasts increase in size in preparation for
lactation.
• The nipples and areola darken.
• Colostrum may be secreted by the nipples in late
pregnancy.
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Slide 46
Antepartal Care
• Sexuality/Reproductive System
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Sexual Activity
• Unless there are complications in the pregnancy or the
bag of water has ruptured, there is no physiological
reason to limit sexual activity during pregnancy.
• Many women experience a decrease in desire as a
result of hormonal changes and the multiple discomforts
that may be occurring.
• Discussion of various coital positions and sexual activity
that does not include intercourse is appropriate.
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Slide 47
Antepartal Care
• Vaginal Bleeding
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Vaginal bleeding at any time during pregnancy should
be reported to the physician at once.
Sexual activity should cease until the cause of the
bleeding is determined and should be resumed only
when the physician determines that no danger exists.
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Slide 48
Antepartal Care
• Coping/Stress Tolerance
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All of the physical and hormonal changes of
pregnancy place additional stress on the woman.
Mood swings and ambivalence are common as the
woman works through her fears and comes to grip
with the reality of pregnancy and how the pregnancy
will affect her life.
Listening and allowing the woman adequate time to
verbalize her fears can also help reduce anxieties.
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Slide 49
Antepartal Care
• Role/Relationship
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Pregnancy introduces a totally new role, that of a
mother.
 Culture will have much to do with how the woman will
define her role.
 Dynamics also change between the woman and the
baby’s father, particularly with the first pregnancy. The
woman is no longer just a wife or girlfriend; she is also
a mother.
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Slide 50
Antepartal Care
• Self-Perception/Self-Concept
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Rapid changes in body shape and size can lead to
changes in self-image.
 Many women feel that they are not attractive when
they are pregnant.
 They may also feel a loss of control related to the
changes taking place.
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Slide 51
Antepartal Care
• Cognitive/Perceptual
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Although sensory changes are uncommon with
pregnancy, blurring or diplopia may indicate problems
with pregnancy-induced hypertension.
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Prenatal education is important.
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Slide 52
Preparation for Childbirth
• Childbirth Preparation Classes
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Some classes are general in nature, whereas others
are targeted toward specific groups such as
adolescents, those having cesarean or vaginal birth
after cesarean delivery, siblings, or grandparents.
Common methods of prepared childbirth include
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Dick-Read
Bradley
Leboyer
Lamaze
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Slide 53
Figure 25-8
(From Lowdermilk, D.L., Perry, S.E. [2004]. Maternity & women’s health care. [8th ed.]. St. Louis:
Mosby.)
Entire family participating in a childbirth preparation course.
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Slide 54
Preparation for Childbirth
• Cultural Variations in Prenatal Care
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It is imperative that the practitioner determine and
explore cultural practices and beliefs with the
patient.
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Slide 55
Nursing Process
• Nursing Diagnoses
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Body image, disturbed
Nutrition: less than body requirements
Injury, risk for
Activity intolerance
Incontinence, stress urinary
Constipation
Sleep pattern, disturbed
Fatigue
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Slide 56
Nursing Process
• Nursing Diagnoses (continued)
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Knowledge, deficient
Family processes, interrupted
Fear
Parenting, risk for impaired
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Slide 57