Physiological changes in pregnancy

Question 1

With the developing foetus in the abdominal cavity, what happens to the; respiratory system?

Answer 1

1. Diaphragmatic breathing

2. Increased tidal volume

Question 2

What is the placental blood flow requirement in ml/minute at term?

Answer 2

600-700ml/min which is 80% of the uterine blood flow

Question 3

What is the oxygen saturation in the foetal circulation?

Answer 3

Around 80%

Question 4

Due to the increased amount of blood needed by the uterus to keep the placenta perfused, what happens to the maternal cardiovascular system?

Answer 4

1. Cardiac output (CO) increases (due to an increased HR and SV)
2. There is a decrease in vascular resistance, explaining the increased SV
3. BP reduces in pregnancy

Question 5

What happens to plasma volume in pregnancy that explains the common presence of oedema?

Answer 5

Plasma volume increases by about 40%

Question 6

What is a worrying change to the haematological system during pregnancy?

Answer 6

All pregnant women are in a HYPERCOAGUABLE state therefore at increased risk of PE and DVT

Question 7

What are pregnant women more at risk of developing haematologically?

Answer 7

Anaemia - this is because there is a greater increase in plasma volume than RBC so they are unproportionate