Physiology of Pregnancy

Question 1

What happens to systemic vascular resistance during pregnancy?

Answer 1

It goes down about 15-20%

Question 2

What part of the placenta is responsible for the remodelling of the local spiral arteries to lower their resistance?

Answer 2

Extravillous trophoblasts– subgroup of the cytotrophoblast

Question 3

Extravillous trophoblasts invade intravascularly to change the spiral arteries into high bloodflow low resistance arteries

Answer 3

ok

Question 4

When, during pregnancy, does this spiral artery remodelling start?

Answer 4

4 weeks

Question 5

Spiral artery remodelling is complete when?

Answer 5

20 weeks

Question 6

Reduced total vascular resistance is due to what?

Answer 6

1) Reduced vasomotor tone

2) remodelling of arteries (even peripheral arteries are remodelled by matrix metalloproteinases)

Question 7

In a mother with pre-eclampsia, what will VEGF receptor 1 levels be compared to a normal pregnancy?

Answer 7

High

Question 8

cGMP is important to what process

Answer 8

vessel relaxation…should be higher in normal pregnancy

Question 9

Increased large artery compliance in combination with lower peripheral vascular resistance means what for afterload?

Answer 9

Afterload (pressure against which teh ventricular walls contract….pressure against cardiac output…..will be decreased

Question 10

We know that plasma volume increases during pregnancy. What happens when plasma volume doesn’t increase by a great enough amount

Answer 10

IUGR of the fetus

Question 11

What happens to hematocrit (RBC concentration) in pregnancy?

Answer 11

It falls. This is because blood volume goes up and erythrogenesis (red blood cell creation) cannot increase at a high enough rate

Question 12

Preload during pregnancy

Answer 12

goes up

Question 13

Cardiac output during pregnancy?

Answer 13

goes up

Question 14

Ventricular remodelling during pregnancy results in left ventricular hyperplasia

Answer 14

ok. This same kind of hyperplasia is seen in athletes

Question 15

Increased Med 13

Answer 15

increased energy expenditure, low fat storage

Question 16

Deletion of Med 13

Answer 16

increased susceptibility to diet induced obesity, increased glucose intolerance and incidence of fatty liver

Question 17

What happens to GFR during pregnancy>

Answer 17

Increases by about 50%

Question 18

Serum creatinine during pregnancy?

Answer 18

Decreased because of increased GFR. serum creatinine levels that are normally seen in an unpregnant woman present in a pregnanct woman may mean there is underlying kidney disease

Question 19

Remember, a level of hydronephrosis during pregnancy is normal because of the smooth muscle relaxation in the ureters and compression of the ureters by the growing fetus.

Answer 19

This hydronephrosis is more prominent on the right side

Question 20

Effect of pregnancy on the diaphragm?

Answer 20

Raises it by about 4cm

Question 21

Rib cage during pregnancy

Answer 21

raises and widens

Question 22

Abdominal muscle tone during pregnancy?

Answer 22

lost

Question 23

This loss of abdominal muscle tone means that they are a less active part of respiration and that respiration during pregnancy is driven by the diaphragm.

Answer 23

ok

Question 24

Inspiratory capacity during pregnancy?

Answer 24

Increases, due to increased tidal volume and smaller residual capacity

Question 25

Alveolar ventilation?

Answer 25

Increases

Question 26

Maternal hyperventilation is a protective measure in what way?

Answer 26

It prevents the fetus from being overexposed to CO2

Question 27

What does leptin do during pregnancy?

Answer 27

goes up

Question 28

Where does the majority of leptin come from during pregnancy

Answer 28

the placenta

Question 29

Usually increased leptin increases satiety and suppresses appetite

Answer 29

during pregnancy, we are letpin resistant….just like in obesity.

Question 30

Cortisol levels during pregnancy

Answer 30

rise…apparently the placenta secretes CRH

Question 31

What enzyme is responsible for converting maternal cortisol (active glucocorticoids) to fetal corticosterone (inert)

Answer 31

11 Beta HSD2….KNOW!!!

Question 32

Deficiency in 11 beta HSD2 means

Answer 32

higher levels of cortisol get to the fetus. Causes low birthweight, altered HPA axis, long term neuro-psychic sequelae.

Question 33

11 Beta HSD2 in pre-eclampsia?

Answer 33

Decreased

Question 34

11 Beta HSD2 is very important for protection from maternal cortisol

Answer 34

ok

Question 35

Four mechanisms of maternofetal transfer

Answer 35

• Endocytosis, exocytosis: uptake from maternal blood by ENDOCYTOSIS, transport across cytosol via VESICULAR TRANS, released into fetal circulation via EXOCYTOSIS
• Lipophillic diffusion
• Paracellular Diffusion
• Protein Mediated Transport

Question 36

Placental tissue uptakes what type of fatty acid preferentially

Answer 36

Long chain polyunsaturated