8.2 Maternal problems in pregnancy (lecture)

Question 1

what is carried out an antenatal screening?

Answer 1

history + examination
blood test
urinalysis

Question 2

what do you check for in history + examination in antenatal screening?

Answer 2

risk factors e.g. gestational diabetes

Question 3

what do you check for in blood tests in antenatal screening?

Answer 3

1. blood group (mother and foetus) - blood transfusion e.g. C-section, haemorrhage
2. haemoglobin
3. infection

Question 4

why do you check for maternal haemoglobin within a blood test?

Answer 4

the demand on the maternal iron store - baseline measurement of maternal haemoglobin
(check if mother has become anaemic)

Question 5

what do you check for in urinalysis within a blood test at antenatal screening?

Answer 5

protein

baseline measurement, check of proteinuria - for pre-eclampsia

Question 6

which systems undergo physiological changes in pregnancy?

Answer 6

CVS
urinary
respiratory
metabolic
GI
immune

Question 7

what are the metabolic changes that occur during pregnancies?

Answer 7

carbohydrate

thyroid hormones

Question 8

what are the changes undergone by the CVS during pregnancies?

Answer 8

blood volume increases (CO = SV x HR)

therefore CO, SV, HR all increase

Question 9

what are the CVS changes from the first trimester (T1)?

Answer 9

CO: increase 40%
SV: increase 35%
HR: increase 15%
(CO = SV x HR, therefore changes in CO most significant if the other 2 increase)

Systemic vascular resistance decrease 25-30%

Question 10

why does Systemic Vascular Resistance decrease 25-30% from the first trimester (T1)?

Answer 10

release of prostaglandins causes relaxation of SM - including vascular SM

Question 11

what are the changes to blood pressure throughout pregnancy?

Answer 11

T1 + T2: BP decrease (vascular resistance decrease - SM)

T3: BP returns to normal

Question 12

what effects will pregnancy have on pre-load and after-load? why?

Answer 12

pregnancy will increase pre-load and after-load because of increase CO (and HR, SV)

Question 13

what is never increased in pregnancy normally?

Answer 13

SYSTOLIC BP

Question 14

why can pregnancy result in hypotension in T1 + T2?

Answer 14

progesterone effects on SVR

Question 15

why can pregnancy result in hypotension in T3?

Answer 15

aortocaval compression by gravid uterus (pregnant, enlarged uterus)

Question 16

what is aortocaval compression syndrome by gravid uterus? (resulting in hypotension in T3)

Answer 16

compression of the abdominal aorta and inferior vena cava by the gravid uterus when a pregnant woman lies on her back, i.e. in the supine position

Question 17

function of the endothelium within pregnancy?

Answer 17

controls vascular permeability
contributes to the vascular tone

vasodilation in pregnancy

Question 18

how would endothelium in a normal pregnancy appear?

Answer 18

vasodilated (prostaglandins, vascular permeability)

plasma-expanded (increase BV)

Question 19

how does epithelium appear in pre-eclamptic pregnancy?

Answer 19

vasoconstricted

plasma-contracted

Question 20

what is pre-eclampsia?

Answer 20

pregnancy-induced hypertension in association with proteinuria (>0.3 g in 24 hours) with or without oedema. Virtually any organ system may be affected

Question 21

what can cause pre-eclampsia?

Answer 21

1. defect in placentation
2. poor uteroplacental circulation
3. widespread endothelial dysfunction

Question 22

what can pre-eclampsia lead to?

Answer 22

eclampsia

seizures during pregnancy - impact mother and baby

Question 23

what are the effects of pregnancy on the urinary system?

Answer 23

GFR increases
renal plasma flow increases
filtration capacity intact
functional renal reserve decreases as GFR increases

(increase CO, therefore increase GFR (from increase in renal plasma flow))

Question 24

what is the functional renal reserve?

Answer 24

the reserve of glomerular filtration rate (GFR) and renal blood flow

Question 25

within the urinary system, which variables increase during pregnancy?

Answer 25

RPF - 60-80% GFR - 55% creatinine clearance - 40-50% protein excretion: up to 300mg/24 hours

Question 26

within the urinary system, which variables decrease during pregnancy?

Answer 26

urea - 50% uric acid - 33%, but rises with gestation (before birth) bicarbonate: 18-22mmol/L creatinine: 25-75 micromol/L

Question 27

what are the consequences of changes to the urinary system?

Answer 27

1. urinary stasis: - progesterone effect on urinary collecting system --> hydroureter - obstruction 2. UTI: pyelonephritis --> pre-term labour (Compression of uterus on bladder (with hydroureter) can lead to hydronephrosis)

Question 28

what are the anatomical changes to the respiratory system during pregnancy?

Answer 28

1. diaphragm displaced | 2. A-P and transverse diameters of thorax increase (to compensate for the displaced diaphragm)

Question 29

what are the consequences of anatomical and physiological changes to the respiratory system?

Answer 29

1. decreased functional residual capacity (decrease residual volume) 2. vital capacity unchanged (largest in + out), total lung capacity ~ unchanged 3. increased minute + alveolar ventilation 4. increased tidal volume (resting), RR unchanged

Question 30

what are the 2 overall physiological changes to the respiratory system?

Answer 30

1. physiological hyperventilation | 2. 'physiological' dyspnoea (SoB)

Question 31

why does physiological hyperventilation occur?

Answer 31

1. increased metabolic CO2 production (has to excrete foetus CO2 in maternal blood) 2. increased respiratory drive effect of progesterone (stimulate respiration, breath off more CO2) 3. resulting in respiratory alkalosis (high pH), compensated by increased renal bicarbonate excretion (partially)

Question 32

why does 'physiological' dyspnoea occur?

Answer 32

due to progesterone-driven hypERventilation | physiological SoB normal, harder to take in a large breath

Question 33

which variables increase in the respiratory system during pregnancies?

Answer 33

O2 consumption increase 20% resting minute ventilation: 15% (ventilate more, different from RR) tidal volume increase: resting breath breathe in more air PaO2 results in increase

Question 34

which variables decrease in the respiratory system during pregnancies?

Answer 34

functional residual capacity in T3 PaCO2 decrease - physiological hyperventilation

Question 35

which variables remain unchanged in the respiratory system during pregnancies?

Answer 35

``` respiratory rate (RR) vital capacity (max in and out) FEV1 (breath out in first second) ```

Question 36

why is vital capacity unchanged during pregnancy?

Answer 36

although pulmonary function is altered during pregnancy, it is not compromised. Therefore, in the absence of any respiratory condition (ie, asthma), does not induce any mechanical stress on the respiratory efficiency of the pregnant patient

Question 37

what are the carbohydrate metabolism changes during pregnancy?

Answer 37

1. placental transport of glucose: facilitated diffusion (GLUT) 2. pregnancy increases maternal peripheral insulin resistance

Question 38

why does pregnancy increase maternal peripheral insulin resistance?

Answer 38

switches to gluconeogenesis and alternative fuels e.g. fatty A (save glucose for foetus)

Question 39

how are changes to carbohydrate metabolism achieved?

Answer 39

human placental lactogen (like growth hormone) | also prolactin, oestrogen / progesterone, cortisol

Question 40

how does blood glucose change in pregnancy?

Answer 40

1. decrease in fasting blood glucose (to foetus) | 2. increase in post-prandial blood glucose (post meal glucose - prolong in circulation for longer for foetus)