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Flashcards in Pregnancy Deck (55)
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1
Q

What is the role of progesterone in early pregnancy?

A
  1. Suppress milk secretion
  2. Suppress uterine contractions
  3. Suppress hypothalamus and pituitary
2
Q

What is the role of oestrogen in early pregnancy?

A
  1. Increase uterine blood flow

2. Increased vessel growth

3
Q

What occurs to the progesterone:oestrogen ratio in late pregnancy?

A

Stable progesterone with increasing oestrogen

  1. Initiates parturition
  2. Initiates lactation
4
Q

Give five roles of oestrogen during pregnancy

A
  1. Priming agents, including receptors
  2. Growth of uterus and mammary tissue
  3. Behavioural effects
  4. Feedback on hypothalamus
  5. Increases uterine blood flow
5
Q

Give five roles of progesterone during pregnancy

A
  1. Growth of endometrium and myometrium
  2. Growth of mammary tissue
  3. Behavioural effects
  4. Negative feedback on hypothalamus
  5. Inhibition of smooth muscle
6
Q

How does the maternal pituitary gland change during pregnancy?

A

Increases in size by 30-50%

7
Q

When is increased pituitary size clinically significant?

A
  1. Acromegaly, with an already enlarged pituitary gland, may compress the optic chiasm leading to blindness
  2. Vascular accident during delivery can lead to Sheehan’s syndrome
8
Q

What is Sheehan’s syndrome?

A
  1. Failure to lactate and resume menstrual cycles

2. Associated with post-partum haemorrhage

9
Q

What mediates increased calcium uptake?

A

Increase PTH and 1,25DHCC

10
Q

What mediates increased levels of adrenal cortical hormones?

A

Oestrogen-induced increase in binding globulins

11
Q

What is the average weight gain in pregnancy?

A

12.5kg

12
Q

Who tends to gain more weight during pregnancy?

A

Younger, lighter women

13
Q

What contributes to weight gain during pregnancy?

A

60% water

  1. 3L in fetus
  2. 1L in placenta, uterus and amniotic cavity
  3. 3L in maternal tissue fluid
  4. 25L extra plasma

> 3kg fat deposition

14
Q

How does blood volume change in pregnancy?

A

40% increase in plasma volume due to upregulation of renin-angiotensin system

Haemodilution as red cell mass increases less than plasma increase

15
Q

What causes increased red blood cell mass?

A

Increased erythropoiesis

16
Q

How does clotting change?

A
  1. Platelet count falls

2. Clotting factors increase

17
Q

How does blood flow change?

A

Increased cardiac output and heart rate

Decreased resistance

Increased flow to kidneys and skin

18
Q

What is transient high blood pressure?

A

Mild rise in BP during pregnancy or soon after delivery

Not accompanied by oedema or proteinuria

Begins after midpoint of pregnancy

19
Q

What is pre-eclampsia?

A

Commonest cause of hypertension during pregnancy

ABP of at least 140mmHg/90mmHg

Oedema and proteinuria

20
Q

Who is most at risk of pre-eclampsia?

A
  1. First time mothers
  2. Younger than 17 or older than 35
  3. Family history of pre-eclampsia
21
Q

What are the three causes of respiratory changes?

A
  1. Space occupying lesion in abdomen puts upwards pressure on diaphragm
  2. Increased oxygen consumption
  3. Circulating hormone levels
22
Q

When is breathlessness during pregnancy relieved?

A
  1. Pelvic ligament softening at 36 weeks

2. Fetal head descends into pelvis and engages, relieving pressure

23
Q

What does pulmonary ventilation increase to?

A

10L per min

24
Q

What causes increase in pulmonary ventilation?

A

Increased tidal volume

25
Q

What occurs to arterial pCO2 during pregnancy?

A

Decreases due to increased alveolar ventilation

26
Q

What are the gastrointestinal changes that occur in pregnancy?

A
  1. Decreased salivary pH causes caries
  2. Increased abdominal pressure causes heartburn
  3. Reduced gastric tone and motility causes nausea
  4. Piles
27
Q

What are the renal changes that occur in pregnancy?

A
  1. Increased GFR due to increased plasma flow
  2. Increased aldosterone
  3. Sodium retention for fetal growth and volume expansion
  4. Increased erythropoietin production
28
Q

Which hormones induce metabolic changes in pregnancy?

A
  1. Sex steroids
  2. Human placental lactogen
  3. Cortisol
29
Q

How does maternal glucose regulation change?

A
  1. Insulin resistance
  2. Glucose diverted to fetus
  3. Proliferation of pancreatic beta cells to compensate for insulin resistance
  4. Can lead to gestational diabetes
30
Q

What are the early behavioural changes in pregnancy?

A

Relate to food acquisition

Increased thirst and appetite, cravings and aversions, nausea and vomiting

31
Q

What are the late behavioural changes in pregnancy?

A

Sense of fatigue

Reduced food intake

Nesting/restlessness

32
Q

What is the proxy measure of intrauterine growth?

A

Birth weight

33
Q

What are the three causes of a small birth weight?

A
  1. Genes
  2. Prematurity
  3. Intrauterine growth restriction
34
Q

What are the five maternal factors influencing intrauterine growth?

A
  1. Uterine size
  2. Nutrition
  3. Parity
  4. Socioeconomic and other environmental factors
  5. Diseases
35
Q

What is the evidence for the effect of uterine size on intrauterine growth?

A

Reciprocal crosses between Shire and Shetland ponies

Multiple pregnancies

36
Q

What are the most important fetal endocrine factors for influencing intrauterine growth?

A
  1. Insulin

2. Thyroid hormones

37
Q

What is the effect of fetal insulin on fetal growth?

A
  1. Decreased bodyweight

2. Increased fat deposition

38
Q

What is the effect of thyroid hormones on fetal growth?

A
  1. Increased bodyweight

2. Muscle, CNS, bones, wool

39
Q

What is the effect of glucocorticoids on fetal growth?

A
  1. Decreased bodyweight

2. Maturational effects on liver, lungs and gut

40
Q

What does IGF-1 contribute to the development of?

A
  1. Liver

2. Bones

41
Q

What does growth hormone contribute to the development of?

A

Fat deposition

42
Q

What are the properties of fetal haemoglobin?

A
  1. Greater intrinsic oxygen affinity

2. Reduced 2,3DPG affinity

43
Q

What are the two shunts in the fetal heart?

A
  1. Foramen ovale

2. Ductus arteriosus

44
Q

How does the fetal circulation differ from adult circulation?

A
  1. Supplies placenta (55%)
  2. CO is 4x greater
  3. Two sides act in parallel rather than in series
  4. Bypasses lungs
45
Q

What are the changes in fetal lungs in preparation for birth?

A
  1. Breathing movements that facilitate normal lung development
  2. Development of surfactant and elastin in the lungs
46
Q

What are the changes in fetal nutritional activity in preparation for birth?

A
  1. Capacity for hepatic gluconeogenesis
  2. Morphology and digestive capacity of the gut
  3. Hepatic glycogen deposition
  4. Hepatic gluconeogenic enzyme activities
  5. Activities for gut digestive enzymes
47
Q

What are the prepartum effects of cortisol on the liver?

A

Increased glycogen deposition

48
Q

What does the maturation of lung, liver, kidney and gut rely on before birth?

A

Increase in glucocorticoid secretion from the fetal adrenal

49
Q

Why are premature infants at risk of neonatal hypoglycaemia?

A

They have not had enough time to develop glycogen stores as they have not had enough cortisol

50
Q

How does cortisol affect fetal concentrations of other hormones?

A

Increases tri-iodothyronine

Increases adrenaline

51
Q

What are trio-iodothyronine and adrenaline important for?

A

Maturation or functional activation of key tissues essential for neonatal survival

52
Q

What does the maturation of lung, liver, kidney and gut rely on before birth?

A

Increase in glucocorticoid secretion from the fetal adrenal

53
Q

Why are premature infants at risk of neonatal hypoglycaemia?

A

They have not had enough time to develop glycogen stores as they have not had enough cortisol

54
Q

How does cortisol affect fetal concentrations of other hormones?

A

Increases tri-iodothyronine

Increases adrenaline

55
Q

What are trio-iodothyronine and adrenaline important for?

A

Maturation or functional activation of key tissues essential for neonatal survival