Cardiovascular Adaptation to Pregnancy

Question 1

Courneya, 2010

Answer 1

Pregnancy is a spectacular example of the adaptivity of the cardiovascular system

Question 2

Courneya, 2010

Answer 2

Cardiac output is able to increase 30-40% in pregnancy and this can increase another 20% if there are multiples

Question 3

Courneya, 2010

Answer 3

The uteral and placental circulations are rich in oestrogen and progesterone which are vasodilators making them low resistance circulations which helps to reduce the increase in blood pressure during pregnancy

Question 4

Courneya, 2010

Answer 4

There is an increased risk of arrhythmias during pregnancy because the increased blood volume stretches the atria and ventricles which can disturb the electrical conduction system and predispose to arrhythmias, and there have also been reports of increased catecholamine release and adrenoceptor sensitivity which can increase ectopic beats

Question 5

Courneya, 2010

Answer 5

Uterine contractions increase sympathetic nerve activity resulting in an increased blood pressure which counteracts the valsalva-like manouevre that restricts venous return

Question 6

Courneya, 2010

Answer 6

During contractions there is an internal transfusion of blood from the uterine sinusoids to the maternal circulation which increases cardiac preload during contractions to counteract the reduced venous return caused by valsalva-ing