Physiological Changes in Pregnancy Flashcards
What laboratory findings are normal for pregnancy?
Reduced urea, reduced creatinine, increased urinary protein loss
What changes to the cardiovascular system would you expect during pregnancy?
SV up 30%, HR up 15% & cardiac output up 40%
systolic BP is unaltered
diastolic BP is reduced in the 1st and 2nd trimester, returning to non-pregnant levels by term
enlarged uterus may interfere with venous return which can lead to ankle oedema, supine hypotension and varicose veins
What changes to the respiratory system would you expect during pregnancy?
Pulmonary ventilation up by 40%, tidal volume from 500 - 700ml (due to effect of progesterone on respiratory centre)
Oxygen requirements increase by only 20%, therefore over-breathing leads to a fall in pCO2 - this can give rise to a sense of dyspnoea that may be accentuated by elevation of the diaphragm
BMR up 15% - this may be due to increased thyroxine and adrenocortical hormones - women may hence find warm conditions uncomfortable
What changes to the blood would you expect during pregnancy?
Maternal blood volume up 30%, mostly in 2nd half
red cells up 20% but plasma up 50% → Hb falls
Low grade increase in coagulant activity
rise in fibrinogen and Factors VII, VIII, X
increased risk of thromboembolism
fibrinolytic activity is decreased - returns to normal after delivery
Platelet count falls
WCC & ESR rise
What changes to the urinary system would you expect during pregnancy?
blood flow increases by 30%
GFR increases by 30-60%
salt and water reabsorption is increased by elevated sex steroid levels
urinary protein losses increase
trace glycosuria is common due to the increased GFR and reduction in tubular reabsorption of filtered glucose
Changes to the liver in pregnancy?
Unlike renal and uterine blood flow, hepatic blood flow doesn’t change
ALP raised 50%
Albumin levels fall
Changes to the uterus in pregnancy?
100g → 1100g
hyperplasia → hypertrophy later
increase in cervical ectropion & discharge
Braxton-Hicks: non-painful ‘practice contractions’ late in pregnancy (>30 wks)
retroversion may lead to retention (12-16 wks), usually self corrects
