Packet 12 Physiology of Normal Pregnancy Flashcards
T-F—cardiovascular function is increased in pregnancy?
True
T-F—pregnancy induces respiratory acidosis?
False- alkalosis
The increased cardiovascular function found during pregnancy leads to what changes in the kidney tubular function?
proteinuria glycosuria amnio-aciduria increased fluid volume net potassium retention
Is pregnancy a hypo or hyper coagulable state?
hypercoaguable
What plays a very important role in controlling postpartum hemostasis?
uterine decidua
Are pregnant women at an increased risk to venous thromboembolism?
Yes
Can you see skin changes during pregnancy?
yes from hormonal and physical reasons
Which direction is the heart displaced during pregnancy?
up and to the left
What do we see on a heart x ray in a pregnant woman?
cardiomegaly
Generalized softening of all things collagen in the pregnant woman leads to what?
hypertrophy of smooth muscle components
Ventricular wall muscle and end diastolic volume increases without what? what does this lead to?
- increase in end systolic volume or end diastolic pressure
2. increase in compliance and slight reduction in ejection fraction
What percentage increase in plasma volume is seen in pregnancy?
45%
[1.2-1.5 L by 32 weeks to a maximum of 4.7-5.2L]
Why does plasma volume increase during pregnancy?
NO release—>vasodilation—>renin angiotensin aldosterone
Why do pregnant women have an increase in risk for enemia?
Increased volume of plasma outpaces the 25% in RBC amount
How high does pregnant CO increase to? why?
7-12 liters/ min
increased SV and HR
What happens when a pregnant woman lies down to CO?
caval compression and decreases CO by 25%
Do we see an increases in blood flow to the brain or liver during pregnancy?
No
Do we see an increase to uterine blood flow during pregnancy?
yes 10 fold
Besides the uterine, where do we see increased blood flow? how much?
renal, breast and skin
50%
Does systolic pressure remain stable throughout pregnancy?
yes
Does diastolic pressure decrease or increase in pregnancy?
decrease by about 10 mmHg by 28 weeks
What happens to BP of pregnant woman lying down?
both sys and dia. BP decrease
when do we see a slight increase in pulse pressure in the early trimester?
early third trimester
What may be the trigger for an increase in HR, SV and CO?
early decrease in SVR
[seen as early as 5 weeks, lowest at 14-24]
What are the antepartum hemodynamics like? [up, down, same]
up= CO, SV, HR
down= SVR, serum colloid pressure
same= PCWP, CVP or MAP
During the first stage of labor, what increase do we see in CO and in SV?
12-31% in CO
22% in SV
During the second stage of labor what increase do we see in CO?
49% in CO
A contraction pushes how much blood from the uterus to systemic blood?
500ml—-> increase to systolic and diastolic pressures
Why does CO increase about 60-80% 10-15 minutes postpartum? [3 reasons]
- release of venal caval obstruction of uterus.
- auto transfusion of utero-placental blood 500ml
- reapid mobilization of extravascular fluid
When does CO return to pre-labor values after delivery?
1 hour
The left atrial dimensions increased after postpartum and leads to what? when do dimensions decrease?
ANP—-> diuresis and naturesis
[LA dimensions decrease 10 days and LV after 4-6 months]
What increases to stimulate the respiratory centers of the brain?
progesterone
upward displacement of the diaphragm leads to what pulmonary changes?
decrease functional residual capacity, expiratory reserve volume
A 40% increase in tidal volume leads to what in pregnancy?
hyperventilation and hypocapnia
Does respiratory rate change during pregnancy?
No— but increase in tidal volume—> 40% increase in minute ventilation
Hyperventilation leads to what?
hypocapnia which leads to mild respiratory alkalosis
What does mild respiratory alkalosis do?
-shifts O2 dissociation curve left to reduce Hgb offloading of oxygen to the fetus
[i believe this is bad, but compensated by 2,3 BPG with a right shift promoting oxygen release to the fetus]
What happens to renal size and weight during pregnancy?
both increase—
Why is the right renal collecting system possibly more dilated than the left?
dextrorotation [clockwise, but from what vantage point???] of the uterus and the protection of the sigmoid colon
What happens to urinary stasis during pregnancy?
Increases
How long may hydronephrosis [water inside kidney] and hydroureter [distension with urine] persist for after birth?
3-4months
decreased ureteral length and intraurethral closure pressure leads to what?
physiologic stress incontinence
T-F—glomerular filtration rate increases in pregnancy as early as 6 weeks?
True—
Why does GFR increase?
increase CO
vasodilation of vessels pre and post glomerulus
Increase in GFR leads to decreased what that can be measured?
decreased serum creatinine and urea concentrations
Why does increased sodium filtration and excretion occur during pregnancy?
up progesterone–> inhibits aldosterone
up prostaglandins—>vasodilator
up ANP
What does progesterone do to potassium excretion?
it inhibits excretion
T-F—calcium excretion and resorption is balanced during pregnancy?
True
[calcitriol increases intestinal resorption, but there is increased calcium clearance]
T-F—there is increased in glucose reabsorption due to changes in collecting tubule and loop of hence?
False decreased reabsorption so more excretion
T-F—there is increase in uric acid reabsorption?
False—excretion due to decreased reabsorption and increased GFR
Is there an increase in amino acid excretion during pregnancy?
yes—mechanism is largely unknown
What increase in total body water do we see during pregnancy?
2 L intravascular
6-7 L extravascular
Progesterone increases what coagulation factors?
Tissue factor and plasminogen activator inhibitor [at the decimal level]
What plays the primary role in mediating puerperal hemostasis?
Decidual Tissue Factor
What happens to fibrinogen during pregnancy?
doubles [with normal value between 200-400]
What happens to Factors 7, 8, 9, 10 and vWF during pregnancy?
increases 20-1000%
What coagulation factors remain unchanged during pregnancy?
prothrombin and factor 5
What coagulation factor declines modestly in pregnancy? How much are Protein S levels at?
Factor 11
60-70%
T-F—during pregnancy there is a decrease in resistance to Protein C?
Increased resistance
What are the 5 results of all the coagulation and venous changes during pregnancy?
- increased clotting
- decreased anticoagulant activity
- decreased fibrinolysis
- increased venous stasis
- increased risk of venous thromboembolism
What is striae gravid arum?
stretch marks
[occurs late…due to physical stretching and separation of underlying collagen]
What is linea nigra? due to what?
black line occurring late in pregnancy due to melanocyte stimulating hormone from placenta [melanocytes in a line]
What is cholasma?
mask of pregnancy—also due to increase melanocyte stimulating hormone
What is chadwicks sign?
bluish discoloration of vagina, cervix, and labia
[venous congestion
estrogen effect]
What does estrogen do in the pregnant woman? 5 things
- up procoagulant factors
- Up liver synthesis of fibrinogen and binding proteins
- ligamen laxity
- breast duct growth
- withdrawal postpartum leads to lactation
What does progesterone do in the pregnant woman? 6 things
- maintain early preg.
- conserve K
- smooth muscle relax everywhere!!
- hypervent–>alkalosis
- hypertrophy of breast alveoli
- withdrawal postpartum promotes lactation
Does withdrawal of estrogen or progesterone lead to lactation?
Both!
