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.
What is the risk of the kidneys compensating for respiratory alkalosis during pregnancy?
The icnreased excretion of HCO3- ions means there is a reduced HCO3- buffer, so acidosis is more likely to occur during pregnancy.
What metabolic changes occur to the mother during the first half of pregnancy?
ANABOLIC PHASE
- increase insulin:anti insulin levels
- increased lipogenesis
- building up stores for the fetus later in the pregnancy
What metabolic changes occur in the mother in the last half of pregnancy?
CATABOLIC PHASE
- decreased insulin:anti insulin levels
- lipolysis
- increased blood glucose levels available for the fetus
What’s the benefit of increased peripheral insulin resistance during pregnancy?
How does the mother deal with this?
It means less glucose is taken up into the cells, so plasma glucose levels increase, leaving more for the fetus to use.
The mother switches to fatty acids and gluconeogenesis for her fuel.
During pregnancy, what happens to blood levels of ketones, free fatty acids, cholesterol and glucose levels in the mother?
- ketones, free fatty acids and cholesterol all increase (the mother i know using this for her fuel)
- Glucose transiently increases following a meal (due to increased insulin resistance) But otherwise it has decreased levels because the fetus is using lots of glucose.
Which hormone promotes the metabolic changes that happen during pregnancy?
Human placental lactogen.
oestrogen, progesterone and cortisol also help
What are the effects of Human placental lactogen during pregnancy on metabolism?
- helps inhibit glucose uptake
- increases insulin release
- increases free fatty acid levels
Why is ketoacidosis associated with pregnancy?
Due to low insulin:anti insulin ratio and increase free fatty acid levels in the blood.
Also reduced bicarbonate buffering ability increases risk of acidosis
What is gestational diabetes?
A state of carbohydrat3e intolerance which occur in pregnancy and disappears after pregnancy.
What risks are associated with gestational diabetes?
- Macrosomic fetus
- Stillbirth
- congenital defects
What happens to thryoid levels in pregnancy?
TBG and T3/4 levels are increased.
Free levels of T3 and T4 are the same (due to the increased TBG being able to bind more)
TSH can be decreased (negative feedback)
What stimulated changes to the thyroid gland in pregnancy?
Human chorionic gonadotrophin directly acts on the thyroid gland, increasing T3/4 production.
What anatomical changes happen to the GIT of the mother during pregnancy?
Disposition of the viscera due to the presence of the gravid uterus.
This can be an issue eg appendicitis when the pain may be felt higher up, so clinicians may misinterpret this as coming from the liver etc.
What physiological changes occur to the GIT during pregnancy?
increased relaxation- constipation.
billiary tract stasis (increased risk of gall stones and subsequent pancreatitis)
Due to the action of progesterone which relaxes smooth muscle.
What happens to plasma calcium levels during pregnancy?
How does this change come about?
-they increase, to help mineralise the skeleton of the fetus.
Due to increased levels of PTH and calcitonin, which increase kidney reabsorption and calcium absorption at the intestines.
What happens if calcium intake is not enough during pregnancy?
The fetal skeleton still gets mineralised, Calcium is taken from the maternal skeleton via the actions of calcitonin.
What haematological effects occur in pregnancy?
-prothrombotic state
-increased risk of thromboemboi.
-increased risk of anaemia
-
Why is the maternal body in a prothrombtic state during pregnancy?
In preparation for partuition, in which there will be blood loss.
by increasing clotting factors this will limit blood loss from the mother.
Why is there an increased risk of thromboembolism during pregnancy?
- changes to blood flow- Systemic venodilation leads to increased stasis
- changes to blood composition- pregnancy affects the make up of blood
What are some causes of anaemia in pregnancy?
-dilutional/physiological anemia occurs because the blood volume increases but the red blood cell volume doesnt increase proportionally.
iron deficiency anaemia- the growing fetus uses a lot of iron.
What effects does pregnancy have on the immune system?
generalised immunosupression to prevent rejection of the fetus.
haemolytic diseases of the newborn eg rhesus incompatibility
antibody transfer disease- graves, hashimotos.
What is pre-ecclampsia?
A state the can occur in human pregnancies which involves oedema, hypertension and proteinuria.
It can lead to ecclampsia, which is fitting of the mother with no other definitive cause.
It occurs as a result of plasma volume contraction and vasoconstriction.
Why does hypertension occrur in a pre-ecclamptic mother?
There is systemic vasoconstriction (opposite to what is normally seem),
The plasma volume contraction decreases blood flow to the placenta and fetus, so the compensate the maternal blood pressure is further increased.
What CNS effects may pre-ecclampsia cause?
- headaches
- vision changes
- seizures
- blindness
What renal changes can occur due to pre-ecclampsia?
- proteinuria
- oliguria
- renal failure
What heamatological changes may occur due to preeclampsia?
- DIC
- thrombocytopenia
- heamolysis
- raised liver enzymes
What is the treatment for pre-eclampsia?
Delivery of the baby.
Until this is possible, the mother must be monitored closely and blood pressure managed.
