Obstetrics: Physiology of Pregnancy

Question 1

What week is the peak HCG levels?

Answer 1

Week 9

Question 2

What gestation is the uterus at the umbilicus?

Answer 2

20

Question 3

What gestation is the uterus at the xiphoid process?

Answer 3

36 weeks

Question 4

How much does blood volume increase in pregnancy?

Answer 4

Increases by 30 - 50% (5L - 7.5L) mostly comes from an increase in plasma which is why you get a physiological anaeemia

Question 5

How does the heart rate and cardiac output change in pregnancy?

Answer 5

Heart rate increases by around 20bpm which increases cardiac output. There is also sometimes a split. S1 and a third heart sound

Question 6

What happens to the urinary system during pregnancy?

Answer 6

Increased blood flow to the kidneys - increased GFR and urinary output.
Kidneys enlarge (physiological hydronephrosis)
Ureters enlarge

Question 7

What happens to the blood pressure during pregnancy?

Answer 7

Diastolic BP is reduced in the first trimester and returns to non pregnant levels by term.

Question 8

How does the respiratory system change in pregnancy?

Answer 8

Pulmonary ventilation increases by 40%. tidal volume increases from 500 - 700ml due to the effect of progesterone on respiratory centre.