8.2 Maternal physiology & pregnancy

Question 1

‘normal’ acid-base balance in pregnancy. why?

Answer 1

respiratory alkalosis, compensated by renal bicarb excretion

due to increased minute volume and tidal volume = hyperventilation so low co2

Question 2

why might dyspnoea of pregnancy occur?

Answer 2

decreased PaCO2, and a contribution from hyperventilation

Question 3

2 ways the CVS is adapted

Answer 3

1. volume expansion
2. clotting

Question 4

explain volume expansion of the CVS

Answer 4

early- increased volume
late- increased HR

progesterone relaxes smooth muscle and drops BP

Question 5

explain clotting of CVS

Answer 5

increased procoagulants
decreased anticoagulants
reduced fibrinolysis

Question 6

how is SV increased? consequences?

Answer 6

oestrogen and progesterone activate RAAS
-can result in oedema due to fluid retention
-dilutional anaemia

Question 7

dilution anaemia

Answer 7

not enough RBCs made for the increase in plasma volume, even though RBCs would be bigger

Question 8

consequence of clotting being upregulated

Answer 8

hypercoagulable state so could increase thrombolic events

Question 9

commonest cause of anaemia in pregnancy

Answer 9

iro deficiency

Question 10

why do serum urea and creatinine drop?

Answer 10

GFR increases so more is cleared and excreted

Question 11

cause of glucosuria

Answer 11

decreased PCT absorption

Question 12

why can pregnancy increase risk of UTIs

Answer 12

decreased speed of passage of urine due to smooth muscle relaxation (ureters)

Question 13

overall change to GI system

Answer 13

slow transit time

Question 14

which LFT raised? why?

Answer 14

ALP due to placental synthesis

Question 15

can goitre be normal in pregnancy?

Answer 15

yes due to thyroid stimulation

Question 16

why are T3 and 4 levels raised?

Answer 16

oestrogen stimulates thyroxine binding globulin so need to increase thyroxine

Question 17

risk factors for gestational diabetes

Answer 17

-BMI >30
-previous macrosomic baby weighing >4.5kg
-family history of diabetes
-ethnicity with high diabetes prevalence

Question 18

investigations for gestational diabetes

Answer 18

oral glucose tolerance test for those with risk factors
blood glucose

Question 19

diagnosis of gestational diabetes

Answer 19

fasting plasma glucose 5.6 or above
2 hour plasma glucose 7.8 or above

Question 20

risks of gestational diabetes for mother

Answer 20

-pre eclampsia
-premature labour

-shoulder dystocia
-failure to progress
-T2DM

Question 21

risks of gestational diabetes for baby

Answer 21

-macrosomia
-neural tube defects
-hypoglycaemia
-respiratory distress
-jaundice

Question 22

MSK adaptations

Answer 22

change centre of gravity
-increased lordosis
-forward flexion of neck
-stretch abdo muscles
-increased pubic symphysis mobility
-anterior tilt of pelvis
-fluid retention can compress median nerve

Question 23

‘normal’ skin adaptations. why?

Answer 23

chloasma (tanned face)
palmar erythema
vascular spiders
linea niagra

oestrogen increases melanin

Question 24

risk factors for pre eclampsia

Answer 24

over 40
family history
previous
HTN
BMI 30 or above
multiplie pregnancy

Question 25

when does pre eclampsia occur?

Answer 25

after 20 weeks

Question 26

pathogenesis of pre eclampsia

Answer 26

impaired invasion of trophoblast so shallow invasion of spiral arteries, leads to hypoperfusion and ischaemia and systemic endothelial dysfunction

Question 27

symptoms of pre eclampsia

Answer 27

-headache
-vision disturbance
-epigastric pain
-swelling of hands, feet face
-vomiting
-SOB

Question 28

why SOB in pre eclampsia

Answer 28

fluid on lungs

Question 29

maternal complications of pre eclampsia

Answer 29

-seizure
-cerebral haemorrhgae
-renal failure
-pulomanory oedema

-haemolysis
-elevated liver enxymes
-low platelets
-DIC

Question 30

fetal complications of pre eclampsia

Answer 30

-growth restriction
-oligohydramnios
-placental infarct
-fetal distress
-premature delivery
-still birth

Question 31

oligohydramnios

Answer 31

amniotic fluid deficiency