Physiological adaptations in pregnancy Flashcards
(30 cards)
at 8 weeks during pregnancy, which hormones are secreted by the placenta? [2]
progesteron and oestrogen (and also relaxin)
what changes occur in total blood volume during pregenancy? [1}
what pattern of increase / decrease this occur in? [1]
what is this driven by? [1]
what changes occur in total erythrocyte levels during pregenancy? [1}
what pattern of increase / decrease this occur in? [1]
what is this driven by? [1]
total blood volume:
- total blood volume increases rapidly during first & second trimester (and slowly still in third)
- driven by increased plasma volume (up to 45% increase)
erythrocyte levels:
- overall increase in total rbc cell
- *- dip then incresae**
- (increae is smaller relative to plasma volume)
explain what is meant by dilutional anaemia? [2]
which trimester does it most commonly occur in? [1]
because erythrocyte levels increase during preg at a smaller relative level compared to plasma volume: Hb concentrations fall from around 150gll pre-preg –> 120 g /l during third trimester
what happens to CO during pregnancy? and when? and to what level?
- CO increased by 35/40% in first trimester (& only slightly in 2nd and 3rd): to about 50% at term
what causes the increases in CO seen during pregenancy? [2]
- combined impact of stroke volume increase (25%) & HR increase (25%)
- increase in stroke volume due to:
i) ventricle wall muscle mass increase
ii) heart becomes physiologically dilated and myocardial contracitlity increased
where in the body does the new CO go to? [3]
increase in skin [1] and uterus [1]
decrease (slight) in kidney [1]
what happens to blood pressure during pregnancy? [1]
how does this compare to CO? [1] - how do they interact? [1]
why does this change in BP occur? [2]
- mean arterial BP stays the same of even falls slightly
- MAP = CO X TPR
- CO increases SO peripheral vascular resistance falls by 50% in early pregnancy due to
i) progesterone relaxing smooth muscle
ii) placenta = additional organ with new blood vessel circuit
what is pre-eclampsia characterised by? [1]
what can it cause? [1]
high blood pressure with proteinuria
can cause mother & baby death
what is maternal hypotension? [1]
when does it occur? [1]
what is maternal hypotension? [1]
compression of vena cava - impedes blood return to heart
when does it occur? [1]
during 3rd trimester
pregenant women should not lie in supine position during BP measurements ! in third tri
what is the name of the process of clot dissolution during healing stage of coagulation/ [1]
fibronolysis
what happens to haemostasis during pregnancy? [1]
why is it thought this occurs? [2]
hypercoagulable state: increased blood clotting state
helps to prevent xs bleeding during preg & helps placental function
plasma concentrations of fibronogen and all clotting factors except WHAT? [2] gradually increase
plasma concentrations of fibronogen and all clotting factors except XI & tissue factor (TF)] gradually increase
overall pregenancy is asscoaited with a decrease in coagulation inhibitors !
what happens to the following during preg?
platelet production [1]
platelet count [1]
fibrinolysis activity? [1]
what happens to the following during preg?
platelet production [1]
increased
platelet count [1]
decreased (due to dilutional affect of increased plasma volume)
fibrinolysis activity? [1]
inhibited
which condition is at increased risk bc of hypercoagulability that occurs in preg? [1]
thrombosis and thromboembolism
what physiological changes occur in resp system during pregnancy? [3]
which hormone is this due to? [1]
- increased alveolar ventilation
- increased minute ventilation (vol of gas inhaled / exhaled from a persons lungs per minute)
- increased tidal ventilation
- progesterone stimulates the resp centre to directly increase sensitivty to co2. progesterone-mediated hypersensitivity to co2
what happens to PaCO2 and PaO2 during preg c.f non-preg? [2]
pregnancy paCo2: falls
pregenancy paO2: rises
what happens to diaphragm bc of expanding uterus? [1]
what effects does this have on (increase/decrease)
residual vol
expiratory reserve vol
tidal vol
total lung capacity
what happens to diaphragm bc of expanding uterus? [1]
expanding uterus
what effects does this have on (increase/decrease)
residual vol: decrease
expiratory reserve vol: decrease
tidal vol: increase
total lung capacity: decrease
what changes in acid / base balance occurs during preg [1] why [1]
resp alkolosis
hyperpenvtialtion and removal of CO2:causes renal compensation
what changes occur in excretion of urea, creatinine, urate clearance and bicarbonate during preg? [1]
what affect does this have on plasma concs? [1]
what changes occur in excretion of urea, creatinine, urate clearance and bicarbonate during preg? [1]
increased excretion
what affect does this have on plasma concs? [1]
decreased plasma concs
what can occur to glucose levels during pregancy ? name? [1]
what can occur to glucose levels during pregancy? name? [1]
- *decrease in reabsorb of glucose** (due to increase in filtered load of glucose which is greater than the ability of PCT to reabsorb)
- *glycosuria**
what happens in preg to:
prorenin [1]
renin [1]
angiotensinogen [1]
which hormones cause this changes? [1]
what effect does this have? [3]
what happens in preg to:
prorenin [1]: peaks 8-12 weeks after gestation
renin [1]: peaks 20 weeks after gestation
angiotensinogen [1]: siginficant increase throughout
oestrogen increases renin and angiotensinogen
effect:
- *- increased water retention
- increased Na+ & water reabsorb
- decreased sensitivity to AT II to offset its actions on vasoconstriction**
what changes occur in liver function during preg? [1]
high normal / evlevated changes (clinically insignif)
what changes might get in GI function during preg? [7]
- heart burn / reflux common (increae in intra-abd. pressure)
- progesterone mediated reduction in LOS tone
- predispostion to regurgitation and aspiration during anaesthesia
- constipation
- increase in water absorbtion
- haemorrhoid formation
- decrease in tone and motility of small and large bowell
endocrine changes in pregnancy?
- early and later changes in insulin repsonse? [2]
- which conditon likely? [1]
- gestational diabetes (during 3rd trimester, resolves after baby born)
- early preg: increased insulin prod & sensitivity: plasma glucose may fall
- later preg: repsonse blunted by placental hormones and plasma glucose may rise
