4/11 Maternal Adaptation of Pregnancy Flashcards
Given the fetal/pregnancy need for perfusion, what is the maternal response (generally)?
- Volume expansion
- Vasodilation
- incr cardiac output
Given the fetal/pregnancy need for nutrition and oxygenation, what is the maternal response (generally)?
- Incr respiration
- Increased O2 delivery
- Insulin resistance
- Increased intestinal absorption
Given the fetal/pregnancy need for clearance of waste and toxins, what is the maternal response (generally)?
- Incr renal glomerular filtration
- Incr hepatocellular clearance
Given the fetal/pregnancy need for the mother to survive a potential hemorrhage, what is the maternal response (generally)?
-Increaed coagulation
During pregnancy, by how much does the mom’s plasma volume increase?
What is the mechanism for this?
Plasma vol increases by 50% (incr body water of 6-8 L!)
Mech: RAAS system
Increased angiotensinogen and renin activity -> At I converts to At II
AtII acts on adrenal gland to increase Aldosterone
Aldosterone promotes sodium retention
Sodium retention leads to water retention!
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By how much does the mom’s RBC volume increase during pregnancy?
RBC volume increases by ~30%
During pregnancy, how much additional iron does mom’s body require?
At what Hgb level do we worry about iron-deficiency?
(there is increased iron absorption in the gut - duodenum)
Pregnancy requires ~ 1gram additional elemental iron
-Hemoglobin level of <10.5 g/dL anytime during preg is likely iron-deficiency anemia
What is physiologic anemia of pregnancy? How does it occur?
Relative dilution of the cellular component of blood (remember the plasma volume expands ~50% but RBC volume expands ~30%).
Therefore the hematocrit and hemoglobin levels fall
She stressed this: during pregnancy, what hemoglobin level defines iron-deficiency anemia?
Normal level of hemoglobin is >10.5 during all trimesters.
Not iron deficiency anemia unless Hgb is < 10.5
how does the increase in total blood volume (40-50%) help a pregnancy?
- Facilitates maternal and fetal exchange of resp gases, nutrients, metabolites
- Supports production of amniotic fluid (by perfusing uterus/plaenta)
- Buffers postpartum blood loss (women lose 500-1000cc at delivery)
–>Maternal hypervolemia is a normal state of pregnancy.
Pregnancy is a hypercoagulable state: what is the mechanism for this?
Why might this be evolutionarily adaptive?
-Increased amts of coagulation factors (I, VII, VIII, IX, X)
Adaptive: prevents excessive bleeding w delivery
Women are hypercoagulable during pregnancy: what is the downside?
(review: elements of Virchow’s triad?)
10x increased rate of venous thrombo-embolism compared to non-preg women (#2 cause of maternal death)
(Virchow’s is fulfilled: hypercoagulability, venous stasis, vascular trauma [@ delivery])
Maternal immune function during preg: generally what occurs?
Generally pregnancy is an immunocompromised state
The uterus, uterine lymphatics, and placenta adapt their immune response to allow the foreign embryo.
Ex: placenta does not express MHC I or MHC II
What are the risks to mom of altered systemic immune function during preg?
specifically what pathogens do we worry about?
Risk of severe complications from some pathogens.
Viral: Influenza, Varicella (major causes of maternal morbidity/mortality)
Bacterial: Listeria
Parasite: Malaria
What are a few changes to the heart/CV system that mimic cardiovascular disease?
- Dyspnea, SOB
- Fatigue
- Decr exercise tolerance
- Peripheral edema
- Systolic Murmur and S3
- Cadriomegaly on CXR
- Heart placed superior, lateral, and anterior due to uterus
Changes to heart sounds during pregnancy?
2 main changes:
Systolic Ejection Murmur (SEM) & S3
(will hear SEM at left sternal border)
Other changes: S1 louder and widely split, S2 persistent splitting, S4 (uncommon), mammary hum due to incr breast blood flow