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!
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