Chapter 4
Physiologic and Psychological
Changes During Pregnancy
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1
Determining Pregnancy and
Physiological Changes
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2
Objectives



Define key terms listed.
Calculate the expected date of delivery and
duration of pregnancy.
Relate the differences among probable,
presumptive, and positive signs of pregnancy.
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3
Objectives (cont.)


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Outline the physiologic changes in
pregnancy.
Explain how pregnancy affects blood volume
and blood plasma.
Describe aortocaval compression or supine
hypotension during pregnancy.
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4
Profile of Previous
Obstetric History
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GTPALM
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G: gravida
T: term pregnancies
P: premature births
A: abortions
L: live births
M: multiple gestations and births
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5
Profile of Previous
Obstetric History (cont.)


G: gravida
P: para
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6
Determining Date of Birth

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EDD: estimated date of delivery
Nägele’s rule:



Identify first day of last normal menstrual period
(LNMP)
Count backward 3 months
Add 7 days
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7
Duration of Pregnancy


Calculated in 28-day month calendar, called
lunar months
10 lunar months in a full-term pregnancy


40 weeks
280 days on average
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8
Trimester

Pregnancy broken out into 3-month segments
called trimesters


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First trimester: first 14 weeks
Second trimester: 15 to 28 weeks
Third trimester: 29 weeks to delivery
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9
Pregnancy Terms



Terminates before fetus reaches 20 weeks
gestation: abortion (lay term is miscarriage)
Terminates after 20th week but before full
term is reached: preterm (premature) birth
Terminates 2 weeks after EDD, or 42 weeks:
postterm birth
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10
Signs of Pregnancy

Presumptive signs


Probable signs


Suggest pregnancy
Likely pregnant
Positive signs

Definite evidence of pregnancy
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11
Three Signs that
Define Pregnancy


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Hearing fetal heart sounds
Palpation of active fetal movements
Visualization of a developing fetus via
ultrasound
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12
Pregnancy Tests

Presence of the hormone human chorionic
gonadotropin (hCG)



Produced by the chorionic villi of the placenta
Can be found in woman’s urine as early as 1
week postconception
PROBABLE indicator of pregnancy
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13
Physiologic Changes
in Body Systems
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14
Major Sources of Change


Hormonal (endocrine system)
Mechanical pressure (physical changes
within the body)
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15
Changes in the Endocrine
System


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Essential to maintain pregnancy
Initially produced by corpus luteum
Later by placenta

A temporary endocrine organ
 Role is to produce high levels of estrogen and
progesterone
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16
Human Placental Lactogen (hPL)


Increases maternal insulin resistance during
pregnancy
Provides fetus with glucose needed for
growth
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17
Changes in the
Reproductive System
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18
Uterus

Enlarges during pregnancy
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

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Increase in size of preexisting muscle cells
(hypertrophy)
Formation of new cells (hyperplasia)
Circulatory requirements increase as it
enlarges
Growth stimulated by hormones

Pressure of growing fetus against uterine wall
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19
Cervix


Becomes shorter and softer during pregnancy
Prepares for



Thinning (effacement)
Enlargement (dilation)
Softening caused by


Hormones leading to increased blood supply
Increase in cervical gland secretions
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Ovaries

Follicles cease to develop to maturity


Ovulation does not occur
Corpus luteum produces estrogen and
progesterone for first 7 to 10 weeks until
placenta can take over

Also produces relaxin
• Thought to help relax symphysis pubis and pelvic joint,
and softens cervix
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21
Vagina



Wall thickens, becomes more pliable, and
expandable
Rugae (folds) more prominent
Discharge increases, leads to increased
glycogen, which increases risk of vaginal
infection

pH decreases (becomes more acidic), preventing
growth of harmful microbes
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22
Breasts


Hormones prepare breasts for lactation
Rapidly enlarge during first 8 weeks of
gestation


Vascular engorgement
Beginning in 9th week


Ductal growth stimulated by estrogen
Alveolar hypertrophy stimulated by progesterone
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23
Breast Changes

Size increases

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Pigmentation of areola and nipple darkens
Montgomery’s glands more prominent


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Become fuller, more sensitive, and tender
Lubricate and protect nipples
Striae may occur
Colostrum excretion as early as 10th week
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24
Initiation of Lactation

Profound drop in estrogen and progesterone


After delivery of placenta
Increase in prolactin

Responsible for milk production
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25
Changes in the
Cardiovascular System
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Cardiovascular


Deliver oxygen and nutrients
Blood must be at pressures sufficient to meet
placental circulation



10% of maternal output channeled to uterine blood
flow in third trimester
Greatest increase occurs during labor and
delivery
More vulnerable to thrombus formation
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27
Supine Hypotensive Syndrome
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Changes in Respiratory System

Thoracic circumference increases



Lung capacity remains the same
Inspiration increases

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
Allows greater intake of oxygen
Expiration increases


Hormonal influence
Allows greater removal of carbon dioxide
Breathing changes from abdominal to
thoracic
Oxygen consumption increased by 15-40%
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29
Dyspnea



Respiratory system has increased sensitivity
due to progesterone
Pressure of uterus on diaphragm
Normally does not interfere with activities of
daily living
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30
Epistaxis

Nosebleeds and nasal stuffiness common


Likely from increased vascularity related to
estrogen
Voice may become deeper

Vocal cords increase in size, likely due to
progesterone
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31
Changes in the GI System


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Gum hypertrophy
Saliva production increased (ptyalism)
Nausea and/or vomiting, especially in first
trimester
Constipation



Due to increase in progesterone and relaxin
Pyrosis (heartburn)
Carbohydrate metabolism altered
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32
Compression of Abdominal
Contents
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33
Audience Response System
Question 1
The two major sources of the physiological
changes during pregnancy are the physical
changes (enlargement of uterus) and the:
A.
B.
C.
D.
Respiratory system
Musculoskeletal system
Gastrointestinal system
Endocrine system
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34
Physiological, Psychological and
Developmental Changes in
Pregnancy
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35
Objectives




Explain why frequency of urination occurs
early and late in pregnancy.
Recognize the changes in skin pigmentation
during pregnancy.
Discuss the influence of pregnancy on the
skeletal system.
Differentiate the risk categories assigned to
drugs as they relate to use during pregnancy.
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36
Objectives (cont.)



Summarize the psychological changes that
occur during pregnancy.
Describe the developmental tasks of
pregnancy.
Discuss the impact on and special needs of
pregnancy for the adolescent, single parent,
and extended family.
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37
Changes in the Renal System



Early and late pregnancy increase in bladder
pressure
Ureters dilate from smooth muscle relaxation
Increased risk of pyelonephritis if woman has
asymptomatic bacteriuria
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38
Fluid and Electrolyte Balance

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Increased glomerular filtration rate
Increased sodium filtration (up to 50%)
Tubular reabsorption (up to 99% reabsorption
of sodium)
Increases risk of sodium retention
Blood more alkaline

Enhanced by hyperventilation
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39
Changes in the Integumentary
and Skeletal Systems

Relaxin and placental progesterone





Relaxation and softening of pelvic joints
Widening of symphysis pubis
Facilitates delivery of fetus
Center of gravity shifts forward as uterus
enlarges
May experience difficulty with balance
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40
Lordosis

Lordosis
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Changes in the Skeletal System



Uterus stretches round ligaments
Woman may develop diastasis recti
abdominis
Increased risk of carpal tunnel syndrome
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42
Changes in the Integumentary
System



Chloasma (“mask of
pregnancy”)
Linea nigra (dark
line on abdomen)
Striae gravidarum
(stretch marks)
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43
Effect of Pregnancy and
Lactation on Medication Ingestion

Subtherapeutic levels may occur due to
increased




Plasma volume
Cardiac output
Glomerular filtration
Decreased gastric emptying

Changes absorption and can delay onset of action
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44
Effect of Pregnancy
on Medication Ingestion

Parenteral medications may absorb more
rapidly due to



Increased levels of estrogen and
progesterone may alter hepatic function


Increased blood flow
Faster onset of action
Results in increased drug accumulation
Some drugs can cross placenta
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45
Effect of Lactation and
Medications


Some drugs pass into breast milk
If lactating, mother must take medication
immediately after infant breastfeeds
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46
FDA Pregnancy Risk Categories





Category A: no demonstrated risk to fetus in
any trimester
Category B: no adverse effects in animals, no
human studies available
Category C: only prescribed after risk to fetus
is considered
Category D: definite fetal risks
Category X: absolute fetal anomalies
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47
Psychological Changes
During Pregnancy






Body image changes
Emotional security
Cultural expectations
Support from partner
Whether pregnancy is unexpected
Financial situations
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48
Psychological Changes
During Pregnancy (cont.)

Major factors that influence the psychological
impact of pregnancy



A woman’s level of maturity
Readiness for childbearing
Hormones contribute to mood swings
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49
Body Image

Considered from four aspects




Appearance
Function
Sensation
Mobility
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50
Responses to Pregnancy
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51
Developmental Tasks




Pregnancy validation
Fetal embodiment
Fetal distinction
Role transition
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52
Pregnant Women May
Experience






Emotional lability
Heightened sensitivity
Increased need for affection
Greater irritability
Fear
Anxiety
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53
Impact on the Father

Announcement


Adjustment


Pregnancy confirmed
Faces reality of pregnancy, asks questions
Focus

May begin to feel like a parent
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54
Impact on the Adolescent

May be fraught with conflict



Dealing with being a teenager and becoming a
parent
Anxiety from having to tell parents
May have financial problems, shame, guilt,
relationship problems with father of baby,
feelings of low self-esteem
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55
Impact on the Adolescent (cont.)

Assess




Developmental and educational level
Support system
Age
The younger the adolescent, the more
difficulty one may see in considering the
needs of others
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56
Impact on the Older Couple

Factors contributing to delayed pregnancy




Effective birth control alternatives
Increasing career options
High cost of living
Development of fertilization techniques to enable
pregnancy later in life
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57
Impact on the Older Couple
(cont.)


Because of age, may encounter special
problems during the labor and delivery
process
Usually adjust to pregnancy because of
factors such as



Often well-educated
Have achieved life experiences, goals
Ready for a lifestyle change
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58
Impact on the Single Mother




May have emotional needs
May have difficulty completing tasks of
pregnancy
May see pregnancy as financial burden, or
may have planned for the event
Social acceptance not as difficult
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59
Impact on the Single Father



May take active interest in and financial
responsibility for child
May want to participate in plans for the child
Participation may not be accepted by the
mother
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60
Impact on the Grandparents


May eagerly anticipate the baby’s arrival or
feel they are not ready for their new role
Level of involvement in baby’s life may be an
issue, based on




Distance
Relationship between parents and grandparents
Role expectations
Different beliefs regarding child-rearing
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61
Audience Response System
Question 2
Name at least two signs that:
A. May suggest pregnancy (presumptive)
B. Strongly indicate pregnancy (probable)
C. Confirm pregnancy (positive)
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62
Review Key Points
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63