Physiologic Changes in Pregnancy

Question 1

Common physiologic changes in pregnancy: renal/urinary

Answer 1

• increased GFR, decreased BUN/Cr
  
  • mechanism = increased CO and renal blood flow due to progesterone
  • increased renal excretion
• urinary frequency, nocturia
  
  • increased urine output, sodium excretion
• mild hyponatremia
  
  • hormones reset threshold for increased ADH release from pituitary

Question 2

Common physiologic changes in pregnancy: Heme

Answer 2

• dilutional anemia
  
  • 2/2 increased plasma volume and RBC mass
• prothrombotic state
  
  • hormone-mediated decrease in total protein S antigen and activity
  • increase in fibrinogen and coagulation facotrs

Question 3

Common physiologic changes in pregnancy: CV/Pulm

Answer 3

• increased CO and HR
  
  • increased blood volume
  • decreased systemic vascular resistance
• chronic respiratory alkalosis w/metabolic compensation (increased PaO2 and decreased PaCO2)
  
  • progesterone directly stimulates central respiratory centers to increase tidal volume and minute ventilation

Question 4

Normal ABG in pregnancy

Answer 4

• pH = 7.45 (increased)
• PCO₂ = 28 (decreased)
• HCO₃ = 18 (decreased)

Question 5

Evaluation of decreased fetal movement

Answer 5

1. NST
2. Contraction stress test (CST)
3. biophysical profile