Transcript Physiologic changes of pregnancy lect 2

Physiologic changes of
pregnancy
Prof. Aziza Tosson
AIMS
 TO
GAIN AN UNDERSTANDING OF THE
PHYSIOLOGICAL CHANGES THAT
OCCUR DURING PREGNANCY
LEARNING OUTCOMES

IDENTIFY THE CHANGES THAT TAKE PLACE
WITHIN THE UTERUS AND BODY SYSTEMS
DURING PREGNANCY

CONSIDER THE EFFECT THESE CHANGES HAVE
ON THE WOMAN

EXPLORE THE ROLE OF THE MIDWIFE WHEN
GIVING ADVISE TO THESE WOMEN
Objectives
 Symptoms
and physical findings of each
organ system
 Physiologic versus pathologic changes
 Diagnostic tests and interpretations
during physiological changes
UNDERSTANDING NEEDED

TO EXPLAIN THE PHYSIOLOGICAL
CHANGES THAT TAKE PLACE TO THE
WOMAN

TO UNDERSTAND THE MINOR
DISORDERS OF PREGNANCY

RECOGNISE PATHOLOGICAL CHANGES IN
ORDER TO REFER APPROPRIATELY
[insert
presenter
info]
Anatomical Changes
 Pelvis
 Pelvic Floor Muscles
 Uterus
 Uterine Ligaments
 Cervix
 Placenta
 Amniotic Fluid
Pelvis
Pelvic Floor Muscles
Abdominal Diastasis
Normal
Diastasis
Physiological Changes
 Circulatory
 Urinary
 Thermoregulation
 Skin
 Metabolic
 Breasts
 Respiratory
 Biomechanical
 Digestive
DEFINITION
THE CHANGES THAT TAKE PLACE IN
THE MATERNAL ORGAN SYSTEM IN
RESPONSE TO PREGNANCY.
TO ACCOMADATE THE PREGNANCY
AND TO PREPARE THE WOMAN FOR
LABOUR
Organ systems
 Cardiovascular
system
 Pulmonary system
 Genital tract
 Urinary system
 Endocrine system
 Gastrointestinal Tract
 Skin
CHANGES ARE DUE TO
 ALTERATIONS
IN

HORMONAL PRODUCTION

CIRCULATION

METABOLISM
HORMONES
OESTROGEN
 Produced
in corpus luteum
 Produced
by placenta after 12 weeks
 Responsible
for growth particularly of
uterus and breasts
progesterone

Produced in corpus luteum and then the
placenta

Relaxes smooth muscle

Inhibits uterine contractions until uterus is
prepared for labour

Regulates storage of body fat
Human chorionic gonadotrophic
 Secreted
from trophoblast of the
developing embryo
 Maintains
corpus luteum until placenta
takes over
 Used
in tests to confirm pregnancy
Human placental lactogen
 Alters
maternal metabolism
 Diverts
glucose to fetus
 Mobilises
stores
free fatty acids from maternal
RELAXIN
 Released
by corpus luteum then the
Placenta
 Softens
pelvic ligaments
 Reduces
myometrial tone
Changes to Body System
 First Trimester



Baby begins to grow
Increased urination
Changes with skin and
hair
 Thickening waistline
 Nausea/fatigue
 Second Trimester





Baby’s weight increases
Energy level improves
Heartburn
Leg cramps
Pelvis relaxes causing SI
discomfort
 Third Trimester
 Baby has more rapid
growth & weight gain
 Backaches
 Swelling of the hands,
legs, and feet
 Breathlessness
 More frequent
urination
Maternal changes - anatomical
and physiological
 Cardiovascular
changes
 increase
in SV
 increase
in cardiac output
 increase
in HR at given work load
 increase
in blood volume (mostly during
latter half of pregnancy)
 Uterus
may compress large blood vessels
reducing venous return
 Total
Body water
Circulatory
System
Cardiovascular Changes
INCREASE
DECREASE

Blood volume

Hematocrit

Cardiac (heart)
output

Blood pressure

Blood supply to uterus

Stroke volume

Cardiac reserve

End diastolic
volume

Vascular resistance

Resting pulse

% of blood plasma
Cardiovascular System

Heart shifts up and to the left

Hemoglobin stays the same (12-16 g/dL) initially
 May drop down to 10 g/dL and still be normal
physiologic anemia.
 Normal pregnancy Hgb is 10-14 g/dL later in
pregnancy
 Decreased Hct (38-47%)
 Normal pregnancy Hct is 32-42 later in pregnancy
 Pulse rate may increase 10-15 beats.
 Weight of uterus can cause supine hypotensive
syndrome.
Wajed Hatamleh RN, MSN, PhD.
Supine hypotension related to
Venal cava syndrome
This leads to dizziness,
air hunger, nausea
Total body water
 Increases
6-8 L
 Increases by 40 %
 Normal body water
 2/3
intracellular
 1/3 extracellular
¾ interstitial
 ¼ intravasular

 2/3
increase is extravascular
Physiologic anemia of
pregnancy

Physiologic intravascular change
 Plasma volume increases 50-70 %


RBC mass increases 20-35 %


Beginning by the 6th wk
Beginning by the 12th wk
Disproportionate increase in plasma volume
over RBC volume----Hemodilution
 Despite erythrocyte production there is a
physiologic fall in the hemoglobin and
hematocrit readings
Iron deficiency anemia

With erythropoiesis of pregnancy, iron
requirements increase.
 Because large amounts of iron may not be
available from body stores and may not be in
the diet
 Supplementation is recommended to prevent
iron deficiency anemia
 At term, Hemoglobin less than 10.0 is usually
due to iron deficiency anemia rather than the
hemodilution of pregnancy
Normal Iron Requirements

Total body iron content average in normal
adult females is 2gm
 Iron requirement for normal pregnancy is 1
gm



200 mg is excreted
300 mg is transferred to fetus
500 mg is need for mom




Total volume of RBC inc is 450 ml
1 ml of RBCs contains 1.1 mg of iron
450 ml X 1.1 mg/ml = 500 mg
Daily average is 6-7 mg/day
 Small intervals between pregnancies are
most concerning
Respiratory system
 Mechanical
 diaphragm
 Consumption
 Increase
in needed oxygen
 Stimulation
 Progesterone
stimulation
Respiratory Changes
 Respiratory capacity
increases
 Shortness of breath
 Pulmonary reserve
decreases
 Increased risk of
muscle soreness
 Tendency to
hyperventilate
RESULT
adjust the intensity level and duration of exercise
Physiologic changes  RESPIRATORY
 increase
SYSTEM
respiratory rate
 increased oxygen consumption
 common are nasal stuffiness,
nosebleeds due to Increased
vascular swelling to nose
Respiratory

Consumption




O2 consumption Increases 15-20 %
50 % of this increase is required by the uterus
Despite increase in oxygen requirements, with the
increase in Cardiac Output and increase in
alveolar ventilation oxygen consumption exceeds
the requirements.
Therefore, arteriovenous oxygen difference falls
and arterial PCO2 falls.
Physiologic changes 
GASTROINTESTINAL
 Digestive
system slow due to
progesterone
 Nausea and vomiting
 Ptyalism: increase salivation
 Heartburn
 Hemorrhoids
 Prolonged gallbladder emptying time
may lead to gall stones
 Bile salt buildup may lead to itching.
Gastrointestinal Tract

Displacement of the stomach and intestines
 Appendix can be displaced to reach the right
flank
 Gastric emptying and intestinal transit times
are delayed secondary to hormonal and
mechanical factors
 Pyrosis is common due to the reflux of
secretions
 Vascular swelling of the gums
 Hemorrhoids due to elevated pressure in
veins
Digestive Changes
 Digestive system slows
 Intestines are pushed up
and to the sides
 Smooth muscle of the
stomach relaxes and can
cause heartburn
 Constipation and hemorrhoids are
common during pregnancy
 Morning sickness
Physiologic changes  METABOLISM
 BMR
increases by 20-25 % during
pregnancy
 Recommended weight gain – 25-35
lb
– 15-25 lb
 Underweight – 25-35 lb
 Overweight
 Need
for increased iron, calcium,
Metabolic Changes
INCREASES IN:
 Insulin level
 Carbohydrate utilization during exercise
as weight increases
 Estrogen
 Progesterone
 Relaxin
 Caloric requirements by ~ 300
calories/day
 Protein and fluid requirements
Genital Tract

Increased vascularity and hyperemia



Vagina
Perineum
Vulva

Increased secretions
 Characteristic violet color of the vagina


Chadwick’s sign
Increased length to the vaginal wall
 Hypertrophy of the papillae of the vaginal
mucosa
Physiologic changes in
pregnancy - Reproductive system
Uterus –
 Enlarges : esp fundal area thickens, then thins
later in preg
 Umbilicus by 20 weeks
 Xyphoid by 36 weeks fundus, Braxton-Hicks
irregular contractions after 4 months
 Cervix – mucous plug, Goodell’s sign, Chadwick’s
sign
 Ovaries –after 11 weeks, the plac prod progesterone
and estrogen

Changes in the cervix
 Length
remains the same
 Increase in width
 Softening after third month due to
oestrogen
 Increased vascularity
 Increased cervical mucosa
 Increased glandular function
changes in size
uterus grows to 30x23x20 at term
weight increases to 900gms
hypertrophy.. Oestrogen causes cells to
increase until 20 weeks gestation
Hyperplasia:- number of cells increase
under the influence of oestrogen
.
After 20 weeks gestation
 Uterine
muscle tissue stretches to allow
fetus to grow
 Progesterone
relaxes the smooth
muscles enabling it to stretch
Relative Uterus Size During
Pregnancy
Figure 28.15
Changes in the shape of the
uterus
elongates during the 1st 10
weeks like a stalk
 Isthmus
 From
 Later
7mm to 2.5cms at 10 weeks
becomes the lower segment with
the globular uterus sitting on top

ORGANISATION OF MUSCLE FIBRES

Inner circular layer
 Surrounds cornua, lower uterine segment and
cervix

Middle layer
 Oblique, crisscross arrangement involved in
contractions to expel fetus

Outer longitudinal layer
 Contracts and retracts thickening the upper
segment
BY 12 WEEKS
 Uterus
is upright and leans slightly to
the right
 No longer a pelvic organ
 Uterus may be palpable above the
pubic bone
 Fetus now occupies most of the uterine
cavity
 Placenta now developed
ND
2
TRIMESTA
 Development
of the upper and lower
uterine segment
 Upper segment, thicker containing
oblique muscles
 Lower segment formed from the
isthmus contains circular and
longitudinal muscles
 Uterus is pear shaped again
 Braxton Hicks contractions
rd
TRIMESTA
3
 Lower
segment formed from isthmus
and contains longitudinal fibres
 Upper segment thick and contains
oblique muscle fibres
 By 36 weeks lower segment measures
8-10cms
 Engagement
 By 38 weeks the cervix is taken up into
the lower segment
BLOOD CHANGES
 Increase
in oestrogen:
new blood vessels formed
growth of existing ones
 Therefore
an increase in blood volume.
BLOOD SUPPLY TO
UTERUS
 Blood
supply pre pregnancy =
10mls/min
 At
40weeks 800 – 900mls/min
 20%
of cardiac output goes to uterus
 Blood
 Red
volume: from 5 litres to 7.5
total volume up by 40-50%
cell mass: rises constantly throughout
pregancy
Up by 20% by end of
pregnancy
PLASMA VOLUME
Increases from 10th week of pregnancy
variable related to parity, fetal weight and
number
Reaches maximum level approx 50%
above non-pregnant levels at 32-34 weeks
then maintained
 50%
rise in plasma volume
 20%
rise in red cell mass
 Heamodilution:
Physiological anaemia
 Most apparent at 32-34 weeks
RENAL SYSTEM
 DILATION
OF THE RENAL VESSELS
 DUE THE EFFECTS OF
PROGESTERONE
 INCREASED
RENAL BLOOD FLOW
 GFR INCREASES BY 60% IN EARLY
PREGNANCY
 SIZE OF PORES INCREASED
Urinary Changes
 Kidneys
grow and filter more
blood as the blood volume
increases
 Become
more susceptible to
bladder and kidney infections
 Bladder
becomes compressed
causing frequent urination and
incontinence
Physiologic changes URINARY
TRACT
Increased
glomerular filtration
rate
Frequency
Infection : Smooth muscle of
bladder relaxes/stasis
Wajed Hatamleh RN, MSN, PhD.
Endocrine

Normal pregnancy physiology shows


Postprandial hyperglycemia


Early switch from glucose to lipids for fuels
Insulin resistance promotes hyperglycemia


To ensure sustained glucose levels for fetus
Accelerated starvation


“lower lows and higher highs”
Resistance-Reduced peripheral uptake of glucose
for a given dose of insulin
Mild fasting hypoglycemia occurs with
elevated FFA, triglycerides,and cholesterol
WATER, WATER, WATER
Hydration is a major concern
during maternal exercise.
 Provide
a ready source of water
 Encourage
frequent water breaks
Insulin resistance
 Anti-insulin
environment is aided by:
 placental lactogen
 Like
growth hormone
 Increases lipolysis and FFA
 Increases tissue resistance to insulin
 Increased
unbound cortisol
 Estrogen and Progesterone may also
exert some anti-insulin effects
Thyroid

Estrogen stimulates Increase in TBG



hCG stimulates thyroid


TSH is reduced
Iodine deficient state


Total T3 and T4 are increased
However the active hormones remains unchanged
Due to Increased renal clearance
To rule out pathologic changes


Early in pregnancy TSH can be used
Later free T4 is needed
Liver
 Liver
morphology unchanged
 Lab Tests similar to liver disease
 Alkaline
phosphatase doubles
 AST, ALT, GGT and bilirubin are slightly
lower
 Decreased plasma albumin
Gallbladder
 Impaired
contraction
 High residual volumes
 Promotion of stasis
 Stasis associated with increased
cholesterol saturation of pregnancy,
supports predisposition of stones
 Intrahepatic cholestasis
 Retained bile salts-pruritus gravidarum
Physiologic changes  INTEGUMENTARY
SYSTEM
These result from stretching of the skin and
hormonal changes
 Linea nigra: pigmentation down middle
line of abd
 Chloasma – “mask of pregnancy”
 Straie: stretch marks of abd, breasts,
thighs and buttocks
 Sweating
Wajed Hatamleh RN, MSN, PhD.
Skin changes
 Chloasma
or melasma gravidarum
 Striae
 Linea
nigra
Skin Changes
 Stretch
marks
 Dark
pigmented line on there abdomen
which is called Linea Nigra
 Pigment
changes on their face and neck
 Small
blood vessels in the face, neck
and upper chest
 MOST
OF THESE RESOLVE AFTER
PREGNANCY
Melasma
Melasma
Melasma
 Also
known as the mask of pregnancy
 More common in dark skin people
 More pronounced in the summer
 Fades a few months after delivery
 Repeated pregnancy can intensify
 Can occur in normal non-pregnant
women with harmless hormonal
imbalances or women on OCPs or depo
Striae
Striae
 Reddish
slightly depressed
 Breasts, thighs, and abdomen
 In future pregnancies they appear as
glistening, silver lines
Linea nigra
Hyperpigmentation
 Melasma
and linea nigra
 Estrogen and progesterone
 Some melanocyte stimulating effect
Breast Changes
 Early in pregnancy,
tenderness and tightness
is common
 After 8 weeks, breasts
grow and blood vessels
often are visible
 Nipples
 A thick
become larger and darker
yellowish fluid can be expressed
from the nipple
MS system
 Joint
relaxation
 Posture changes -lordosis/center of
gravity Back ache
 Diastasis recti: separation of rectus
abdominous
 Leg cramp due to calcium, and
stretching
Wajed Hatamleh RN, MSN, PhD.
Pelvic Floor Muscle Functions
 Maintain
alignment and support of
internal organs
 Control
of urine flow
 Sexual
enhancement
 Eliminate
 Improve
waste from rectum
recovery from episiotomy
Uterus & Uterine Ligaments
Uterus
Round
ligament
Broad
ligament
Biomechanical Changes
 Weight
 Joint
distribution shifts
movement
 Balance
 Spinal
of muscle strength
curves increase
 Joint
laxity becomes greater
 More
structural discomfort
 Increased
potential for nerve compression
Potential for Injury
 Nerve
compression
syndromes
 Low
back discomforts or
pelvic pain
 Upper
back fatigue
 Lower
extremity
 Pelvic
floor function
Postural Dynamics

Increased curve of the waist

Top of pelvis tilts forward

More flexion in the hip joint

Increased hunching in the
upper back and neck

Tailbone is pushed back
Muscles Affected
 Overstretching
& weakening of gluteal
muscles & hamstrings
 Overstretching & weakening of abdominal
muscles & pelvic floor
 Overstretching & weakening of upper back
muscles
 Shortening and tightening of low back & hip
flexors muscles
 Shortening of upper back flexors & pectoral
muscles
Neurological and sensory
 Decreased
intraoccular pressure
 Corneal thickening
 Altered sense of smell
 Decreased attention span
 Problems with memory
 Altered CNS physiology leading to
mood disturbance.
Wajed Hatamleh RN, MSN, PhD.
Combat Effects of Gravity/
Hormones

Do pelvic tilts
 Alter the stance
 Shorten the jog stride
 Lower or eliminate the
step in aerobics
 Avoid rapid leg
abduction
 Avoid breast stroke kick
in swimming
 Recognize tolerance for
activities will vary

Do pelvic floor
exercises to prevent
trauma
 Emphasize
strengthening &
stretching exercises
 Wear abdominal
support/ sports bra
when exercising for
support
Changes
to
Body
System
 First Trimester
 Third Trimester






Baby begins to grow
Increased urination
Changes with skin and hair
Thickening waistline
Nausea/fatigue
Second Trimester





Baby’s weight increases
Energy level improves
Heartburn
Leg cramps
Pelvis relaxes causing SI
discomfort





Baby has more rapid
growth & weight gain
Backaches
Swelling of the hands, legs,
and feet
Breathlessness
More frequent urination