Guess Lecturer - A Good Pregnancy

Question 1

State the cardiac output equation, and define each term.

Answer 1

CO = SV x HR
CO is the amount of blood pumped out of heart in one minute.
SV is the amount of blood pumped out of LV in one beat

Question 2

What is meant by ‘term’?

Answer 2

Ready to give birth, 39-41 weeks

Question 3

During pregnancy, is there increased or decreased vascular resistance? Why?

Answer 3

Peripheral vasodilation causes decreased vascular resistance. Mediated by endothelium-dependent factors e.g. NO and PGI2

Question 4

State the equation that links cardiac output and total peripheral resistance together.

Answer 4

MAP (mean arterial pressure) = CO x TPR

Question 5

What is the result of a reduction in systemic vascular resistance?

Answer 5

Increased cardiac output, predominantly due to increase in stroke volume (lowered resistance allows more blood to be pumped out of LV at each beat), not much change in HR

Question 6

When is CO highest during pregnancy?

Answer 6

20-28 weeks

Question 7

Does CO fall or rise at term?

Answer 7

Small fall

Question 8

Increased circulating vasodilators has what effect on the capacitance of venous/arterial bed ?

Answer 8

Increased capacitance

Question 9

How does peripheral vasodilation affect the kidneys?

Answer 9

Increased blood flow to kidneys, so increased GFR, thus decreased serum creatinine levels (more filtered/excreted)

Question 10

How does peripheral vasodilation affect the extremities, breasts and nasal mucosa?

Answer 10

More blood flow so warm hands and feet, nasal congestion, and breast engorgement.

Question 11

What is the effect of maternal supine position?

Answer 11

Pressure of uterus and fetus on IVC causes reduction in venous return, thus decreased SV and hence CO. Reduces uterine blood flow and may compromise fetus.

Question 12

How does the blood volume change during pregnancy?

Answer 12

Increased blood volume, without increase in red cell mass, causes a relative haemodilution, leading to anaemia of pregnancy.

Question 13

Why is arrhythmogenicity a likely risk factor in pregnancy?

Answer 13

Increased blood volume causes atrial and ventricular stretch, this coupled with catecholamine secretion which results in vasodilation and greater adrenergic receptor sensitivity will increase likelihood of arrhythmogenicity.

Question 14

How is increased stroke volume achieved?

Answer 14

Increase in ventricular wall muscle mass (increased myocardial contractility) and end-diastolic volume (heart is physiologically dilated)

Question 15

How does cardiac output change intra partum?

Answer 15

Further increase.
Uterine contractions, increases SV.
Sympathetic response to pain and anxiety further increases HR and BP

Question 16

What are the effects of cardiac output/stroke volume post partum?

Answer 16

Immediate increase due to relief of IVC obstruction thus increase venous return, and contraction of uterus empties blood into systemic circulation, and transfer of blood from extravascular space increases venous return.

Question 17

Name some cardiovascular symptoms in pregnant women.

Answer 17

Breathlessness, bounding/collapsing pulse
Ejection systolic murmur
Loud first and third heart sound.
Relative sinus tachycardia.
Ectopic beats

Question 18

What are the changes of platelets in pregnant women?

Answer 18

Fall in platelet levels, slow blood clotting.

Question 19

How does the iron requirement change in pregnant women?

Answer 19

2-3x increase in iron requirement.

For certain enzymes and for foetal growth.

Question 20

How does pregnancy achieve a hypercoagulable state?

Answer 20

Increase in fibrinogen, factors, and von Willebrand factor levels. Increase in fibrinolytic inhibitors. Hypercoagulable state in readiness for haemostats following delivery.

Question 21

Why does risk of venous thromboembolism increase?

Answer 21

Venous stasis induced by venous dilation
Obstruction to venous return
Hypercoagulable state
Pro-inflammatory state with activation of endothelial cells

Question 22

How does venous stasis in lower limbs differ from left to right?

Answer 22

Compression of L iliac vein by iliac artery and ovarian artery. No crossing of veins on right side. So venodilatation and decreased flow more marks on the left.

Question 23

Pregnancy is a diabetogenic state. How does insulin requirement change throughout pregnancy?

Answer 23

Initially low requirement. Then insulin secretions increases to counter insulin resistance from higher levels of insulin antagonist.

Question 24

How does protein excretion change in pregnancy?

Answer 24

Greater GFR means increased protein excretion

Question 25

What is hyperemesis gravidarum?

Answer 25

Prolonged vomiting and nausea

Question 26

What is the result of increased peripheral vasodilation?

Answer 26

Increased capacitance of venous and arterial bed, low resistance in uteroplacental circulation –> reduction in systemic vascular resistance

Question 27

How is peripheral vasodilation mediated?

Answer 27

Endothelial-dependent factors:

• NO synthesis upregulated by oestradiol
• prostaglandin

Question 28

Why is pregnancy a diabetogenic state?

Answer 28

Cortisol, progesterone, oestrogen and human placental lactogen are all insulin antagonists. So more glucose remain in blood.

Question 29

How is increased insulin secretion achieved in mid-late pregnancy?

Answer 29

Insulin-secreting pancreatic beta-cells undergo hyperplasia resulting in increased insulin secretion.

Question 30

Increased nutrient availability to the foetus, has what metabolic adaptations in the mother?

Answer 30

Increased postprandial peak blood glucose (less glucose uptake so that more glucose can be available for foetus).
In fasted state, glucose lower than non-pregnancy due to foetal glucose consumption. Maternal reliance on lipolysis and ketogenesis.

Question 31

How does maternal iodine feels change in pregnancy?

Answer 31

Relative maternal iodine deficiency, due to increase of renal loss and activate transport of iodine to foetus.

Question 32

What is the result of insufficient dietary iodine? (hint: thyroid).

Answer 32

Cellular hyperplasia in thyroid and goitre.

Question 33

How does synthesis of T3 and T4 change?

Answer 33

Increased TBG synthesis leads to increase in total T3 and T4

Question 34

How does kidney size change during pregnancy?

Answer 34

Kidney size increases, associated with increase in renal vasculature, interstitial volume and urinary dead space

Question 35

What is pelvicalyceal dilatation, and how does it occur?

Answer 35

Dilation of ureters, renal pelvis and calyces. Due to ureteral smooth muscle relaxation induced by progesterone.

Question 36

How does sodium excretion change in pregnancy?

Answer 36

Decreased ability to excrete sodium due to activation of RAA system and sympathetic nervous system causes greater sodium and water retention.