Describe the cardiovascular changes of pregnancy including parturition.
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.