Physiological changes in pregnancy

Question 1

Plasma volume

Answer 1

1. Increase by 10 - 15 %
2. Expands rapidly until 30 -34 weeks
3. Excess weight gain due to oedema

Question 2

Red cell volume

Answer 2

1. Increase by 20%

2. Haemodilution/Physiological anaemia - Discrepancy between the increase in plasma volume and red blood cell mass

Question 3

Platelets

Answer 3

Slight decrease during pregnancy

Question 4

Clotting factors

Answer 4

1. Pregnancy is a hypercoaguable state

2. Increase in clotting factors especially fibrinogen

Question 5

Cardiac output

Answer 5

1. 5 litres to 6.5 l

2. increase in stroke volume by 10% and pulse rate

Question 6

Blood pressure

Answer 6

1. Drop in peripheral resistance by 50% due to increase in production of vasodilator prostaglandins
2. Diastolic BP drops by mid pregnancy by 10-20 mmHh and increases to non pregnant levels by term

Question 7

Supine hypotension syndrome

Answer 7

1. Lying supine can compress IVC

2. Reduces venous return and cardiac output

Question 8

Respiratory rate changes in pregnancy

Answer 8

1. Breathlessness more common as maternal partial pressure of CO2 is set lower to allow fetus to offload

Question 9

Tidal volume

Answer 9

Increases by 40% due to effect of progesterone

Breathe more deeply but not mor e frequently

Question 10

Skin

Answer 10

1. Linear nigra
2. Palmar Erythema
3. Spide Naevi

Question 11

Effect of pregnancy on the Thyroid

Answer 11

1. Enlarges due to increased demand
2. Increased iodine clearance by kidneys leads to iodide deficiency
3. Increase in TBG, T3 and T4