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 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)
