Flashcards in Pregnancy Deck (176)
What CV changes are made during pregnancy?
Heart adapts to the increased demands via enlarging the uterus and foetus
How much does the resting HR increase by?
How much does the HR increase at each trimester?
5-10 bpm first trimester
15 bpm second and third trimester
What happens in the 2nd and 3rd trimester
- increased oestrogen and chronic gonadotropin stimulates the HR increase
- SNS activation sedentary to maintain BP
how much does Oestrogen and progesterone decrease peripheral vascular
20%, and thus must increase to maintain BP
How much does SV increase?
Why does the increase in blood volume occur?
progesterone increase production if Renin --> sodium reabsorbed --> kidneys reabsorb fluid to the plasma volume
Why is there a LV size increase due to maternal hormones?
- Oestrogen stimulates the myocardial hypertrophy, increasing contractility
- increase blood volume stimulates some myocardial hypertrophy
- growth is eccentric vs. concentric
What is the percentage the SV increase by in the 1st trimester?
What percentage does blood volume increase in?
what is the offset of BP?
increased volume offset by an increase in venous capacitance = blood pressure is not increased
What does the offset of BP cause
problems with postural hypertension
What helps to prevent hyperthermia during exercise?
increase in vasodilation at the skin which increases heat loss
Why can pregnant women become anaemic?
> increase in plasma volume vs red blood cells (increases 20%)
What is the Hb in pre-pregnancy and in the 3rd trimester
Why may blood clotting increase
relaxation of the blood vessel walls with hormonal changes (to keep BP normal after increase in blood volume) from the pressure of the uterus of the interior vena cava
Why may pregnant women develop varicose veins?
exercise assists the blood flow in the legs and feet and helps prevent or minimise these problems
What are the pulmonary adaptations when pregnant?
- elevation of the diaphragm
- uterine enlargement elevated the diaphragm up to 4cm
How much does this reduce reserve volume
why does the rib cage flair outwards?
as it reduces the filling effectiveness
Why is the work of breathing increase at rate and during exercise?
due to the diaphragm resistance
What happens to the respiratory physiological when one is pregnant?
- reduction in total lung capacity occurs
- inspirational capacity remains the same
- reserve volume gets squeezed as a consequence
What does an increased plasma progesterone mean?
stimulate respiratory centre to be more sensitive to CO2
What occurs with hyperventilation?
--> resting hypocapnia (decrease PCO2) --> maternal alkalosis and increased PO2
What does the maternal alkalosis do?
protect against foetal acidosis
when does increase in performance in endurance activities occur?
first 12-15week, before the increase in BW and uterine size reduces or stops involvement in competitive athletics
What does the increase in performance result from
increased blood volume and RBC mass
After the 2nd trimester what happens to the PVO2
- increase O2 demand of foetus
- increase BM
How much does resting O2 increase by?