Session 8 Flashcards
When do most of the Cardiovascular changes occur in pregnancy?
The first trimester
What effect does pregnancy have on Blood volume?
It increases it, probably to account for the blood loss that occurs at delivery - around 2L
What effect does pregnancy have on Cardiac output, Stroke volume and Heart rate?
All increase
What effect does pregnancy have on Blood pressure?
It is never normally increased
Hypotension may occur in the first and second trimester
Why does Hypotension occur in the first and second trimester?
Progesterone has an effect on smooth muscle, causing it to relax so there is less resistance
What other Cardiovascular changes occur in pregnancy?
The apex beat is displaced
Vasodilation of the endothelium
Aortocaval compression due to the gravid uterus
What are the Cardiovascular changes in a Pre-Eclamptic pregnancy?
Vasoconstriction of vessels
Plasma contracted
Why does Pre-Eclampsia occur?
Increase in blood pressure due to placenta defect
Proteinura due to failing of the kidneys
Defect in placentation leads to poor uteroplacental circulation and widespread endothelium dysfunction making a greater demand on the mother. Causing an increase in blood pressure and possibly organ damage
What is Eclampsia?
A seizure that occurs due to the effects of Pre-Eclampsia on the brain
What effect does pregnancy have on the Glomerular Filtration Rate?
It increases - Related to the relaxation effect of Progesterone on smooth muscle
What effect does pregnancy have on the renal plasma flow?
It increases it
What effect does pregnancy have on the Filtration capacity?
It remains intact unless there are disease processes occuring
What effect does pregnancy have on Functional renal reserve?
Decreases as Glomerular Filtration Rate increases
What effect does pregnancy have on Urea?
Decreases to around 50% (Around 3.1mmol/L)
What effect does pregnancy have on Creatinine?
Decreases to around 25-75 micromol/L
What effect does pregnancy have on Creatinine Clearance?
Increases
Why are pregnant females more likely to develop UTIs?
Progesterone’s effect on urinary collecting system can cause urinary stasis which can cause infections, possibly ascending up the urethra to cause Pyelonephritis (Causing pre-term labour)
Can also cause Hydroureter
What anatomical changes occur to the Respiratory system during pregnancy?
Diaphragm displacement
Anterior to Posterior and Transverse diameters of the thorax increase
What physiological changes occur to the Respiratory system during pregnancy?
Increased alveolar ventilation
Increased tidal volume
Unchanged resp rate
What effect does pregnancy have on functional residual capacity?
Decreases
What effect does pregnancy have on vital capacity and total lung capacity?
Unchanged
Why does physiological hyperventilation occur in pregnancy?
There is an increased metabolic production of CO2 due to the foetus.
There is an increased respiratory drive due to progesterone’s effect on the respiratory centre in the brain
Respiratory alkalosis compensated for by increased renal bicarbonate excretion
How is glucose transported across the placenta?
Facilitated diffusion
How does pregnancy effect glucose metabolism?
There is an increased resistance to insulin
Gluconeogenesis is used with alternative fuels
What changes the metabolism of glucose in pregnancy?
Human Placental Lactogen - HPL (& Prolactin, Cortisol, Oestrgen/Progesterone)
What is Gestational diabetes?
Carbohydrate intolerance first recognised in pregnancy and not persisting after delivery
Oral glucose test required
What are the risks associated with poorly controlled Gestational diabetes?
Macrosomic foetus (Large) Still birth Increased rate of congenital defects
What effect does pregnancy have on Lipolysis?
Causes it to increase from the second trimester
What effect does progesterone have on appetite?
Increases it so fat stores can be laid down ready for pregnancy
What effect does pregnancy have on free Fatty Acids?
Increase in the plasma on fasting so there is a substrate for the maternal metabolism, leaving glucose for the foetus
Do Fatty Acids cross the placental membrane?
They tend not to, there is also an increased risk of acidosis in the mother
How does pregnancy effect the thyroid?
Thyroid binding globulin is increased which causes T3 & T4 to be increased too.
Free T4 still remains in the same range
hCG decreases TSH production
What anatomical changes occur to the GI system in pregnancy?
Alternatives in the place of the viscera eg appendix moves to URQ
What physiological changes occur to the GI system in pregnancy?
Smooth muscle relaxation due to progesterone, can cause delayed emptying
What is there an increased risk of in pregnancy? (Regarding the GI system)
Pancreatitis - possibly due to the increased lipids
Gall stones/Cholecystitis - due to changes in bile salt concentration
What haematological changes occur during pregnancy?
Pro thrombotic state
Increased fibrin deposition at the implantation site
Increased fibrinogen & clotting factors
Decreased fibrinolysis
What risk is associated with pregnancy? (Regarding Haematological changes)
Increased risk of thrombi forming due to changes and stasis and venodilation
Thromboembolic disease in pregnancy
BUT cannot give warfarin due to its ability to cross the placenta and being tetratogenic
Why is there an increased risk of anaemia during pregnancy?
The plasma volume increases
Red cell mass increases, but not by as much
Physiological anaemia
Have to be aware that pathological anaemia may occur due to iron or folate deficiency too
What changes occur to the immune system during pregnancy?
The foetus is an allograft, therefore changes have to occur to permit survival
There is local non specific suppression of the immune response at the maternal/foetal interface
Antibodies are transferred to the foetus (IgG)
What causes Haemolytic disease of the newborn?
Anti Rhesus antigens go to the foetus which has Rhesus antibodies on its red blood cells. These are then destroyed leading to anaemia
Can a foetus inherit graves disease/Hashimotos disease from the mother?
Yes, as its autoimmune the antigens can cross the placental membrane and cause the same disease in the foetus
