S6) Maternal Physiological Adaptations in Pregnancy Flashcards

1
Q

Identify the 3 types of changes in maternal physiological adaptation to pregnancy

A
  • Biochemical changes
  • Physiological changes
  • Structural changes
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2
Q

Why do maternal physiological adaptations to pregnancy occur?

A
  • Provide a suitable environment for the nutrition, growth and development of the foetus
  • Prepare the mother for birth
  • Prepare the mother for support of the new born
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3
Q

Identify the 6 hormones which orchestrate maternal physiological adaptations to pregnancy

A
  • hCG
  • Progesterone
  • Oestrogen
  • Relaxin
  • hPL
  • Inhibin
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4
Q

hCG is released from the synctiotrophoblast.

What role does it have in early pregnancy?

A

hCG mimics the action of LH and maintains the corpus luteum so it can produce oestrogen and progesterone until the placenta can take over

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5
Q

hCG reduces the maternal levels of IgA, IgG and IgM.

Why is this beneficial to the foetal-placental unit?

A

The maternal antibodies do not attack the foetus as a foreign antigen

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6
Q

hCG reduces the maternal levels of IgA, IgG and IgM.

What consequence does this have on the mother?

A

The mother becomes slightly immunodeficient and is at increased risk of developing infections

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7
Q

Progesterone relaxes smooth muscle.

Identify 4 effects of increasing progesterone levels on the GI tract function which the mother may complain of?

A
  • Vomiting
  • Constipation
  • Heartburn
  • Indigestion
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8
Q

Which oestrogen level in the maternal serum/urine best indicates foetal progress and why?

A

Oestriol (E3) as it shows the development of the liver and has its own singular pathway

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9
Q

Identify 3 hormones which stimulate breast growth

A
  • Oestrogen
  • Progesterone
  • Prolactin
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10
Q

How does inhibin (from the corpus luteum and placenta) prevent further pregnancies from occuring in the pregnant state?

A

Inhibin prevents follicular development by inhibiting FSH

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11
Q

Glucose and amino acid metabolism are altered in pregnancy to favour the nutritional supply to the foetus.

Identify 4 of these changes

A
  • Reduction in maternal [blood glucose] and [amino acid]
  • Diminished maternal response to insulin in second ½ of pregnancy
  • Increased maternal free fatty acid, ketone and triglyceride levels
  • Increased insulin release in response to a normal meal
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12
Q

Identify the 4 hormones which orchestrate the changes in glucose and amino acid metabolism in pregnancy

A
  • Prolactin
  • Oestrogen
  • Progesterone
  • hPL
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13
Q

What effect does progesterone have on glucose metabolism?

A

Progesterone stimulates appetite in the first half of pregnancy and diverts glucose into fat synthesis

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14
Q

What effect does oestrogen have on glucose metabolism?

A

Oestrogen stimulates an increase in prolactin release

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15
Q

Identify the 3 main hormones responsible for maternal resistance to insulin

A
  • Prolactin
  • hPL
  • Cortisol
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16
Q

Describe the significance of maternal decline in glucose usage

A
  • Gluconeogenesis increases, maximising the availability of glucose to the foetus
  • Maternal energy demands are met by fatty acid metabolism (later in pregnancy)
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17
Q

What is the benefit of increased maternal deposition of fat by progesterone?

A

Prepares for higher energy demands from the foetus later in pregnancy

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18
Q

Which hormone is primarily responsible for changes in maternal carbohydrate metabolism during pregnancy?

A

Human placental lactogen (hPL)

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19
Q

As pregnancy progresses, the foetal-placental unit’s increasing nutritional needs aren’t met via maternal vascular-neogenesis.

Describe 2 changes which accomodate this

A

Changes in the function of maternal baroreceptors and volume receptors:

  • Increased blood flow to the growing breasts, kidneys and Gi tract
  • Plasma volume increases while peripheral vascular resistance falls
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20
Q

Identify 2 changes to the maternal heart which can be observed on examination

A
  • Hypertrophy (eccentric)
  • Upward displacement of flow murmurs
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21
Q

Plasma volume increases by 50% in pregnancy due to increased cardiac output. However, progesterone constantly increases too and relaxes smooth muscle.

What overall effect does this have on maternal BP?

A

BP = CO x TPR

  • CO increases
  • TPR decreases
  • Notable increases/decreases in BP (fluctuations)
22
Q

Identify 3 signs and symptoms of fluctuations in maternal BP

A
  • Hot flushes
  • Increased venous pooling
  • Cankles (oedema in the feet)
23
Q

Which 2 factors contribute to venous engorgement and distension seen in later pregnancy?

A
  • Gravity increases venous pooling
  • TPR decrease as less pressure pushes venous blood
24
Q

Identify the 2 long-term sequelae that are attributed to a longer period of venous distension

A
  • Varicose veins
  • Haemorrhoids
25
Q

Identify 3 major complications in pregnancy

A
  • Gestational diabetes
  • Anaemia
  • Pre-eclampsia
26
Q

What is Gestational diabetes?

A
  • Gestational diabetes is high blood sugar that develops during pregnancy due to insufficient insulin production for pregnancy demands
  • It commonly occurs in the second ½ of pregnancy and usually disappears after giving birth
27
Q

If gestational diabetes is not controlled, how will the sustained hyperglycaemia affect foetal glucose levels?

A

Baby grows larger than normal resulting in:

  • Difficulties pushing the baby through the birth canal
  • Presdisposition of neonate to Type II diabetes
28
Q

State 3 complications associated with poorly controlled maternal diabetes

A
  • Jaundice
  • Hypoglycaemia after birth
  • Increased risk of birth defects to brain, heart & spinal cord
29
Q

What is iron deficiency anaemia?

A

Iron deficiency anaemia is the reduction in the amount of healthy RBCs in blood due to a lack of iron

30
Q

Identify 3 clinical features of blood which increase during pregnancy

A
  • Plasma volume
  • Blood volume
  • Red cell mass
31
Q

Which foetal demand does a high plasma flow meet?

A

Increased plasma flow provides high nutritional flow for foetus

32
Q

Which foetal demand does a high blood volume and high red cell mass meet?

A

The following provides increased O2 supply:

  • Increased red cell mass (stimulated by erythropoietin)
  • Increased haemoglobin flow (blood volume)
33
Q

Why does anaemia occur during pregnancy?

A
  • More iron is used for haemoglobin to transfer O2 to foetus
  • High iron turnover due to haemoglobin breakdown > production
34
Q

State 3 signs and symptoms a mother would experience if she has anaemia

A
  • Fatigue
  • Pallor
  • Dizziness
35
Q

What treatments can be given to alleviate the symptoms of anaemia in pregnancy?

A
  • Iron supplements
  • Folate supplements (helps with iron absorption)
36
Q

Predict 2 consequences of poor foetal-placental perfusion associated with anaemia in pregnancy

A
  • Under-development issues: poor neurodevelopment & poor growth
  • Anaemia/hypoxic baby
37
Q

What effect does smoking during pregnancy have on the foetus?

A
  • Tar accumulates and reduces ventilation ability
  • Alveoli cannot diffuse enough O2 into blood
  • Results in poor foetal-placental perfusion
38
Q

What is pre-eclampsia?

A

Pre-eclampsia is a rapidly progessive disorder occuring only during pregnancy and the postpartum period characterized by hypertension and usually the proteinuria

39
Q

What are the diagnostic criteria for pre-eclampsia?

A
  • Systolic BP of 140/more
  • Diastolic BP of 90/more
40
Q

Other than proteinuria and hypertension, identify 5 other symptoms of pre-eclampsia

A
  • Oedema
  • Headache
  • Nausea/vomiting
  • Changes in vision
  • Poor tendon reflexes
41
Q

What signs or symptoms suggest that a mild pre-eclampsia is worsening in severity?

A
  • Decreased kidney function: increased creatinine, urea, urate and creatine clearance

- Decreased liver function: increased AST and gamma-GT

42
Q

Identify 2 examinations performed on a patient with suspected pre-eclampsia

A
  • Examination of optic fundi
  • Examination of tendon reflexes
43
Q

Why would diseases of the respiratory system be more severe in pregnancy?

A

There is an increased oxygen requirement in gestation

44
Q

Describe the changes in respiratory function which occur in pregnancy

A
  • RR changes little
  • Increased tidal volume and oxygen uptake
45
Q

What is the effect of the increased tidal volume and oxygen uptake that is seen in pregnancy?

A
  • Increased awareness of the desire to breathe (interpreted as dyspnoea)
  • Lower pCO2
46
Q

What role does progesterone have in the changes in respiratory function observed in pregnancy?

A

Progesterone acts on the chemoreceptors in the respiratory centre to induce increased respiratory effort and reduction in pCO2

47
Q

What anatomical/mechanical effect does the expanding uterus have on the maternal respiratory system?

A

The expanding uterus pushes up on the xiphoid process and reduces room for lung expansion, hence reducing respiratory function

48
Q

How does the renal function change during pregnancy?

A
  • Increased renal blood flow raises GFR to 160% of normal
  • Increased secretion of renin, aldosterone, angiotensin II compensate for expected sodium loss
49
Q

What effect does the gravid uterus have on renal function?

A
  • The gravid uterus rises from the pelvis and rest upon the ureters
  • This compresses the ureters above the pelvic brim causing renal congestion
50
Q

Pregnancy may be associated with increased urinary incontinence.

Why is this?

A

Gravid uterus places increased pressure on the bladder therefore the mother urinates more frequently

51
Q

Why is there an increased risk of urinary tract infections in pregnancy?

A
  • Progesterone dilates smooth muscle in the nephrons
  • Results in pooling of urine in the distended parts of the urinary system
52
Q

The placenta also contributes to the maternal synthesis of DHCC (calcitriol).

How does this active form of Vitamin D3 contribute to foetal growth?

A

Calcitriol in mother increases calcium reabsorption for the foetus to use for bone growth