Read Dr. Chen Yu Sui’s notes. This is just a brief summary of the changes in the body of a pregnant mother.

  • Enlarging uterus elevates the diaphragm
    • displaces heart upwards & to the left
  • Increase blood volume
    • plasma volume increase
      • plasma renin & aldosterone increase
      • but reduced sensitivity to angiotensin (less vasoconstrictive action)
    • Red cell volume increase
      • slower rate than plasma volume
      • haemodilution: plasma volume increase at a higher rate
        • physiologic anaemia
        • improved in last weeks of pregnancy when there is increase in erythropoiesis
    • left ventricular hypertrophy
    • increase cardiac output
    • Increase of venous return
      • stretch of right atrium = ANF increase
    • increased liver size
      • increase in circulating blood volume
  • Heart rate increases
    • after delivery, heart rate still increased by 5%, although decreased by 15% from pregnancy
  • hPL & progesterone stimulate erythropoiesis
  • increased blood flow to kidney, uterus & skin
  • Predipheral  vasodilation, decreased resistance
    • by oestrodiol, progesterone & local prostaglandins
    • uteroplacental circulation, higher blood flow
  • Systolic & diastolic pressure
    • decrease in 1st trimester
    • rise again by full term
    • decrease in diastolic pressure higher
  • Reduced colloid osmotic pressure
    • due to haemodilution
  • Increase in venous pressure in lower extremities
    • vasodilation increases venous blood
    • increased blood volume
    • compress pelvic veins & inferior vena cava by uterus enlargement
  • Dependent oedema
    • reduced osmolic collid pressure
    • increased venous pressure
  • Respiratory adaptation
    • decrease in lung height due to enlarging uterus, but compensated by increased in chest circumference (diameter)
    • change from abdominal to thoracic breathing
    • relaxation of smooth muscle in the tracheobronchial tree
    • increase in minute ventilation
      • hyperventilation due to increased progesterone
      • respiratory rate might also remain unchanged
    • increase in TV, decrease in  FRC, RV & ERV
  • O2 comsumption increases during final weeks of pregnancy
    • BMR increases
  • pH increase
    • due to increased removal of CO2
    • pCO2 decreased
  • Increased immature RBC
    • increased Diphosphate gylcerol
      • by product of RBC metabolite
      • decrease affinity of O2
      • more dissociation of O2 from haemoglobin
  • Increased neutrophil count
  • Increased platelet consumption (decrease platelet count)
    • increased hypercoagulating state
    • plasma fibrinolytic activity depressed
      • due to placentral inhibitors
      • risk of thrombosis (immobility deep vein thrombosis)
  • Renal plasma flow increased
    • GFR increases
      • decrease in creatinine & urea
    • uterus pressure on urinary bladder
      • frequent urinary
    • Na+ excretion
      • ANF
      • progesterone
      • Increased GFR
        • opposed by aldosterone, oestrodiol, deoxycorticosterone
  • Increased glucose excretion
    • glycosuria
    • max TbG reabsorption same during pregnancy
  • Urinary protein excretion
    • in normal person, no proteinuria
  • Insulin secretion
    • hyperinsulinemia in pregnancy
    • insulin resistance later
      • more glucose available for foetal needs
      • increased mobilisation and utilisation of FA & ketones for energy production
    • Later half of pregnancy, hPL, prolactin, maternal cortisol & glucagon
      • oppose effects of insulin
  • weight increases
    • due to water retention
    • higher with multiple pregnancy
  • Nausea & vomiting
  • Heartburn
    • gastric reflux
      • relaxation of lower oesophageal sphincter
      • delayed gastric emptying
      • increased intragastric pressure
      • decreased intraoesophageal pressure
  • Constipation
    • decreased colon motility
    • increased water absorption from colon
    • pressure from enlarging uterus

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