Repro 8.2 Maternal problems in pregnancy Flashcards
What systems undergo changes during pregnancy?
- Cardiovascular
- respiratory
- gastrointestinal
- immune system
- Urinary system
- Haemolytic system
- Metabolism
What changes occur to the CVS during pregnancy?
- Blood volume increases by up to 50%
- Cardiac output, stroke volume and heart rate all increase
- Blood pressure falls
- vascular resistance decreases
Why do changes happen to the CVS system during pregnancy?
- to prepare for partuition
- to provide for the foetus and placenta.
What happens to the blood pressure over the course of a pregnancy?
T1 and T2- decreased
T3 normal.
Systolic blood pressure should not change throughout/
What causes the increase in blood volume during pregnancy?
Oestrogen and progesterone affect the RAAS system, and reduce water and sodium excretion, therefore blood volume increases.
What effects do progesterone and oestrogen have on the CVS during pregnancy?
- increase blood volume (by alterring RAAS and causing retention of sodium and water)
- decrease peripheral resistance by causing systemic vasodilation
What should be considered when measuring a pregnant woman’s blood pressure?
You should not measure her BP whilst lying supine becuase the gravid uterus can compress the IVC, reducing blood return to the heart, so the patient will become hypotensive.
What is the condition known as when a pregnant woman’s blood pressure is taken lying down?
Supine hypotensive syndrome.
What effects does pregnancy have on the urinary system?
- Increased GFR
- Increased creatinine, protein clearance
- relaxation of the collecting systems.
Why does GFR increase during pregnancy?
progesterone leads to vasodilation of the afferent arteriole, increasing the amount of blood going to the kidneys and being filtered.
What happens to blood levels of urea, creatinine and bicarbonate ions during pregnancy?
Why?
They all decrease.
Urea and creatinine due to increased clearance.
Bicarbonate due to compensation of physiological respiratory alkalosis by increasing excretion of HCO3-
Why might you detect glucose in the urine of a pregnant woman?
there is an increased GFR and renal blood flow, but there is a fixed reabsoprtive capacity of the PCT, so only a certain amount of glucose can be reabsorbed.
If this limit gets exceeded, the remaining glucose will be excreted into the urine.
Why are pregnant women more prone to UTI’s?
How is this avoided?
- relaxation of the ureters causes stasis of urine, which is an ideal breeding ground for bacteria.
- immune system becomes compromised in the pregnant state.
- Each time a pregnant woman goes for a check up she will have a urine dip stick to test for any UTI’s so they can get treated early.
What urinary pathology are pregnant females more likely to encounter?
- UTI
- Pyelonephritis
- Hydronephrosis (due to relaxation of the ureters, and the slow movement of urine)
- AKI (secondary to pyelonephritis)
- renal stones
What anatomical changes happen to the respiratory system during pregnancy?
- Displacement of the diaphragm due to the presence of the gravid uterus
- increased AP and transverse diameter of the thoracic cavity
What physiological changes happen to the respiratory system during pregnancy?
- increased tidal volume
- increased alveolar ventilation
- increased minute ventilatory volume
- decreased functional residual capacity
- phsyiological hyperventilation
What is ‘physiological hyperventilation’ in pregnancy?
What can this cause?
progesterone causes an increased respiratory drive which causes dyspnoea.
This can lead to hyperventilation where too much CO2 is being blown off.
As a result respiratory alkalaemia can develop.
This is compensated for by the kidneys which excrete bicarbonate ions.