Physiology of Pregnancy Flashcards
What happens to systemic vascular resistance during pregnancy?
It goes down about 15-20%
What part of the placenta is responsible for the remodelling of the local spiral arteries to lower their resistance?
Extravillous trophoblasts– subgroup of the cytotrophoblast
Extravillous trophoblasts invade intravascularly to change the spiral arteries into high bloodflow low resistance arteries
ok
When, during pregnancy, does this spiral artery remodelling start?
4 weeks
Spiral artery remodelling is complete when?
20 weeks
Reduced total vascular resistance is due to what?
1) Reduced vasomotor tone
2) remodelling of arteries (even peripheral arteries are remodelled by matrix metalloproteinases)
In a mother with pre-eclampsia, what will VEGF receptor 1 levels be compared to a normal pregnancy?
High
cGMP is important to what process
vessel relaxation…should be higher in normal pregnancy
Increased large artery compliance in combination with lower peripheral vascular resistance means what for afterload?
Afterload (pressure against which teh ventricular walls contract….pressure against cardiac output…..will be decreased
We know that plasma volume increases during pregnancy. What happens when plasma volume doesn’t increase by a great enough amount
IUGR of the fetus
What happens to hematocrit (RBC concentration) in pregnancy?
It falls. This is because blood volume goes up and erythrogenesis (red blood cell creation) cannot increase at a high enough rate
Preload during pregnancy
goes up
Cardiac output during pregnancy?
goes up
Ventricular remodelling during pregnancy results in left ventricular hyperplasia
ok. This same kind of hyperplasia is seen in athletes
Increased Med 13
increased energy expenditure, low fat storage
Deletion of Med 13
increased susceptibility to diet induced obesity, increased glucose intolerance and incidence of fatty liver
What happens to GFR during pregnancy>
Increases by about 50%
Serum creatinine during pregnancy?
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
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.
This hydronephrosis is more prominent on the right side
Effect of pregnancy on the diaphragm?
Raises it by about 4cm
Rib cage during pregnancy
raises and widens
Abdominal muscle tone during pregnancy?
lost
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.
ok
Inspiratory capacity during pregnancy?
Increases, due to increased tidal volume and smaller residual capacity
Alveolar ventilation?
Increases
Maternal hyperventilation is a protective measure in what way?
It prevents the fetus from being overexposed to CO2
What does leptin do during pregnancy?
goes up
Where does the majority of leptin come from during pregnancy
the placenta
Usually increased leptin increases satiety and suppresses appetite
during pregnancy, we are letpin resistant….just like in obesity.
Cortisol levels during pregnancy
rise…apparently the placenta secretes CRH
What enzyme is responsible for converting maternal cortisol (active glucocorticoids) to fetal corticosterone (inert)
11 Beta HSD2….KNOW!!!
Deficiency in 11 beta HSD2 means
higher levels of cortisol get to the fetus. Causes low birthweight, altered HPA axis, long term neuro-psychic sequelae.
11 Beta HSD2 in pre-eclampsia?
Decreased
11 Beta HSD2 is very important for protection from maternal cortisol
ok
Four mechanisms of maternofetal transfer
- 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
Placental tissue uptakes what type of fatty acid preferentially
Long chain polyunsaturated
