Question 7

Describe the cardiovascular changes of pregnancy including parturition.

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College Answer

Significant CVS changes can occur by eight weeks and then progressively over the term of the 
pregnancy. Structured answers helped candidates avoid missing important areas of the 
answer. It was expected candidates could detail the major changes such as a 40 – 50% 
increase in blood volume, a 30 – 50% increase in cardiac output, a slight decrease in blood 
pressure, the heart size and position changes, the impact of aortocaval compression and 
alterations in colloid osmotic pressure. Some mention of the changes during labour and 
delivery was expected noting uterine contraction squeezes blood to maternal circulation (auto 
transfusion), cardiac output increases (immediately after delivery up by about 60 – 80%) and 
blood pressure increases (both systolic and diastolic) during labour. 
Hormones, particularly the effects of foetoplacental production or transformation of hormones, 
and their cardiovascular effects, especially on total body composition / filling pressures were 
under explained. The cardiovascular changes at parturition were not well explained.