Physiological adaptations in pregnancy Flashcards
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
why does CO increase during labout? [2]
Cardiac output increases during labour and this is due to autotransfusion (blood pushed back into system) from the contracting uterus. The further increase in blood may be auto-transfused as the placenta is delivered.
Pain or anxiety and stimulation of the sympathetic nervous system also increases heart rate and possibly blood pressure.
what systemic postpartum changes occur?
which hormones regulate development of non-pregnany mammary glands [2]
how does pregnant mammary glands change? [3] due to which hormones? !! [3]
which hormones regulate development of non-pregnany mammary glands [2]
progesterone
oestrogen
how does pregnant mammary glands change?
lobular ductal-alveolar system undergoes hypertrophy
adipose tissue deposition
proliferation of ducts
due to:
estradoil
progesterone
placental peptide hormone
(growth hormone and prolactin may also have a role)
which hormone initiates milk production?
prolactin
FSH
oestrogen
oxytocin
progesterone
which hormone initiates milk production?
prolactin
FSH
oestrogen
oxytocin
progesterone
which hormones inhibit secretrory acitivity of mammary tissue? [2]
prolactin
FSH
oestrogen
oxytocin
progesterone
which hormones inhibit secretrory acitivity of mammary tissue?
prolactin
FSH
oestrogen
oxytocin
progesterone
lactogensis occurs by fall in ^^ levels
milk ejection / suckling relfex is triggered by
prolactin
FSH
oestrogen
oxytocin
progesterone
milk ejection / suckling relfex is triggered by
prolactin
FSH
oestrogen
oxytocin: released in reponse to contraction. causes contraction of myoepithelial cells
progesterone
