Maternal Adaption of the Circulatory System Flashcards Preview

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Flashcards in Maternal Adaption of the Circulatory System Deck (16)
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1
Q

From the 7th week of pregnancy, how much can the heart rate increase by?

A

20%

2
Q

Why does the heart rate increase during pregnancy?

A

To compensate for a decrease in systemic vascular resistance (caused by progesterone)

3
Q

Why does cardiac output decrease during pregnancy?

A

As the heart rate increases, diastolic filling time is reduced so less blood is being pumped out with each beat

4
Q

What effect does an increase in heart rate have on atrial emptying?

A

It reduces the efficientcy

5
Q

What is blood pressure?

A

Cardiac output x Systemic vascular resistance

6
Q

From the 7th week of pregnancy, how much can blood pressure decrease by?

A

10% as a result of peripheral vasodilation

7
Q

As blood pressure falls, does the cardiac output increase or decrease?

A

Increases

8
Q

At how many weeks of pregnancy would you expect blood pressure to be at its lowest?

A

24 weeks

9
Q

What is the normal average cardiac output and what is the average cardiac output during pregnancy?

A

5 litres per minute - normal

7.2 litres per minute during pregnancy

10
Q

Between which weeks of pregnancy is systemic vascular resistance at its lowest?

A

14-24 weeks

11
Q

During labour, what causes blood from the uterus to return to the maternal circulation?

A

Contractions

12
Q

How many milliliters of blood can be shifted back to the maternal circulation with each contraction?

A

Up to 500 milliliters

13
Q

As blood is returned to the maternal circulatory system, what effect does this have on:
Venous Return
Cardiac Output

A

Both increase

14
Q

What is haemodilution?

A

The increase in plasma volume causing the blood to become diluted

15
Q

By what percentage does the red blood cell mass increase by?

A

18-25%

16
Q

What happens to the white blood cell count and the platelet count?

A

White cell increases

Platelets fall