8.2

Question 1

Describe the CVS changes in pregnancy?

Answer 1

CO 40% increase
SV 35% increase
Heart rate 15% increase
Blood volume Increase

Systemic vascular resistance 25/30% decrease
Blood pressure decreases

Question 2

How does BP change in pregnancy?

Answer 2

• Systolic BP is never increased in Pregnancy (normally)

• Hypotension in Pregnancy
o T1 and T2 – Progesterone effects on Systemic Vascular Resistance (SMV)
o T3 – Aortocaval compression by gravid uterus. Reduced return to the heart.

Question 3

How is endothelium involved in pregnancy?

Answer 3

• Endothelium
o Controls vascular permeability
o Contributes to the control of vascular tone
• Vasodilation of pregnancy

Question 4

How does GFR change in pregnancy?

Answer 4

Increases by 55%

Question 5

What increases in renal system of pregnancy?

Answer 5

GFR
Creatine clearance
Protein excretion

Question 6

What decreases in renal system of pregnancy?

Answer 6

Urea
Uric acid
Bicarbonate
Creatinine

Question 7

Why does urinary stasis occur in pregnancy? What can this result in?

Answer 7

• Progesterone relaxes the smooth muscle in the walls of the ureters, which can result in stasis, hydroureter, UTIs and pyelonephritis.
• Pyelonephritis can induce pre-term labour.

Question 8

How does the respiratory system change in pregnancy?

Answer 8

• Diaphragm is displaced

* A-P and transverse diameters of thorax increase

Question 9

How does oxygen consumption, FRC, VC, TV, Alveolar ventilation rate change?

Answer 9

O2 Increase
FRC Decrease
VC Unchanged
TV Increase
AVR Increase

Question 10

How does the mother deal with the extra CO2 from the fetus?

Answer 10

During pregnancy there is a physiological hyperventilation driven by progesterone, so the mother can blow off the extra CO2 the fetus produces.
• Increased metabolic CO2 production
• Increased respiratory drive effect of progesterone
o Physiological dyspnoea
• Resulting in respiratory alkalosis, compensated by increased renal bicarbonate secretion (less reabsorption)

Question 11

How does carbohydrate metabolism change in the first half of pregnancy?

Answer 11

Progesterone stimulates appetits - diverts glucose into fat synthesis.
Oesterogen stimulates an increase in prolactin release - generates a maternal resistance to insulin.

Maternal glucose use declines and gluconeogenesis
- maximises glucose for fetus.

Question 12

How is the maternal insulin resistance achieved?

Answer 12

Human placental lactogen
Prolactin
Oesterogen
Progesterone 
Cortisol

Question 13

How does blood glucose change in pregnancy?

Answer 13

• Decrease in fasting blood glucose

* Increase in post-meal (post-prandial) blood glucose

Question 14

What is gestational diabetes?

Answer 14

Pancreas is unable to respond to metabolic demand of pregnancy with beta cell hyperplasia and hypertrophy and increased rate of insulin synthesis.

Loss of metabolic control and blood glucose increases.

Disappears after birth

Question 15

Risk factors for gestational diabetes

Answer 15

> 25yo
Family or personal health history
Excess weight.

Question 16

Describe lipid metabolism changes in pregnancy. Risk?

Answer 16

• Increase in lipolysis from T2
• Increase in plasma concentration of free fatty acids on fasting
o Free fatty acids provide substrate for maternal metabolism, leaving glucose for the fetus
• Increased utilisation of free fatty acids increases the risk of Ketoacidosis
o Combined with pregnancy’s state of compensated respiratory alkalosis this can be extremely bad.