Physiology of Pregnancy Flashcards
Amount that cardiac output increases. Due to?
30-50%. Increase in stroke volume then heart rate
What happens to systemic vascular resistance? Due to?
Decreases. Due to elevated Progesterone — relaxes smooth muscle
How much does blood pressure decrease?
SBP: minus 5-10 mmHg
DBP: minus 10-15 mmHg
How much does tidal volume increase? How does this affect PAO2 and PACO2?
30-40%.
Increases PAO2 (and PaO2) while decreasing CO2
What is the significance of an decreased PaCO2? Due to?
Elevated Progesterone increases respiratory system’s responsiveness to CO2. The increased gradient facilitates O2 delivery to fetus (and thus CO2 removal)
% of pregnancies wherein mothers suffer from N&V? What is it due to? When does it resolve?
70%. Due to estrogen, progesterone, and B-hCG increases. Resolves by 14-16 wks
What changes contribute to acid reflux and ptyalism (spitting) and constipation?
Prolonged gastric emptying, decreased sphincter tone, decreased large bowel motility
% increase in GFR? What is it’s significance?
50%. Causes decrease in BUN/Cr by 25%.
% increase in plasma volume? % increase in RBC volume? Significance?
50% in plasma, but only 20-30% RBC –> Dilutional anemia
WBC Increase?
mean 10.5 mil/mL
Why is pregnancy considered a hypercoagulable state?
Elevated fibrinogen and Factors VII –> X
Venous stasis
Endothelial damage
What produces increase in Estrogen?
Placenta (and a little bit ovaries)
Describe estrogen production in the ovaries
Ovarian theca cells –> estrogen precursors –> transfer to Ovarian granulosa cells
Describe estrogen production in placenta
Maternal adrenal glands produce precursors
What is the composition of B-hCG?
2 alpha, 2 beta subunits.
alpha subunit = alpha subunit of LH, FSH, TSH (but beta subunit is different)
Describe the role of the placenta.
–> B-hCG (which maintains the corpus luteum in early pregnancy).
–> Progesterone (maintain endometrium)
–> Human Placental Lactogen/HPL (induces lipolysis and FA formation for fetal nutrition; insulin antagonist)
Describe changes in thyroid hormones during pregnancy, even though pregnancy is considered euthyroid.
Estrogen stimulates TBG (total T3 and T4 levels increase but Free T3/T4 stay same)
B-hCG (~TSH) stimulates thyroid (T3, T4 increase slightly)
MSK and Derm changes in pregnancy
carpal tunnel
back pain
Average kcal requirement per day?
Caloric increase requirement if breastfeeding?
2000 –> 2500 kcal/d (+300 kcal/day)
If breastfeeding +500 kcal/day
Protein requirement?
70-75 g/day
Recommended calcium intake
1.5 g/day
Folate requirements
400 micrograms/day
4 mg/d if hx. NTDs
