Maternal Adaptations to Pregnancy

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  • Created by: Becca
  • Created on: 29-12-13 20:46
What physical changes happen during pregnancy?
Uterus enlarges, endometrial changes to support implantation/invasion/fetal growth, mammary gland development, sealing of cervix, increased ventricular wall muscle, weight gain (increased maternal blood vol, placenta, baby), change maternal bone [Ca]
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What cardiovascular changes happen during pregnancy?
Increase cardiac output (heart rate + stroke volume) & decrease in peripheral resistance (relaxed vascular tone, rise blood vol) -> overall fall in BP (lowest mid pregnancy, normal by term), decreased venous return (uterus can occlude vena cava)
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What haematological changes happen during pregnancy?
Increase in maternal oxygen consumption & pulmonary ventilation, PCO2 decreases: benefits fetus, maximises PO2 on maternal side, drives O2 to fetus. Increase total Hb but plasma vol rises -> dilution drop in Hb, haematocrit & red cell count -> oedema
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What iron & B vitamin changes happen during pregnancy?
Iron: increased intestinal iron absorption, placenta rich in transferrin (allows release of Fe into ST->fetus). B vit: B12 & B9 (folate) needed for DNA/RNA synthesis. B12 in meat/poultry/fish/milk, B9 in beans/dark leafy veg/poultry/liver/marmite
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What anatomical & physiological renal changes happen during pregnancy?
Kidneys enlarge (increase vascular vol+interstitial space), calyces/pelvis/ureter dilate (progesterone, local pressure effects), increased risk of UTI. Increase renal plasma flow, decrease renal vascular resistance & changes in tubular re-absorption
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What renal haemodynamic alterations happen during pregnancy?
Renal plasma flow (RPF) increases to mid-pregnancy, decreases 3rd trimester. Glomerular filtration rate increases but less than RPF. Filtration fraction declines in early pregnancy
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How does the renal handling of glucose change during pregnancy?
Glucose reabsorption increase until threshold reached, maximal reabsorptive capacity falls, increased renal flow means there is more glucose in the filtrate. Filtered glucose load exceeds max rate of reabsorption->raised glucose excretion->glycosuria
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How does glucose haemostasis change through pregnancy?
Early pregnancy: progesterone increases maternal appetite, insulin secretive favours fat storage. Mid pregnancy onwards: increase glucose absorption/glucongeogenesis, mobilisation of FFA by placental lactogen, mild insulin resistance etc
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How does the foetus avoid maternal rejection?
Placenta structural barrier, ST doesn't have histocompatibility antigens (immunological barrier). Maternal cells entering cytoplasm destroyed by lysosomal system. If they transcytose to the placenta, macrophages phagocytose maternal immune cells
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Which immune cells are in the endometrium? How is immunity different in the endometrium?
Dendritic (APC), helper/regulatory T cells, uterine NK cells. Endometrial mucosa must mount immune response whilst tolerating sperm & allogenic fetus, immune cells interact via soluble factors
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What is the role of extravillous trophoblast cells (EVTs)?
EVTs invade endometrium & remodel spiral arteries, HLA-G isn't expressed so can be used to suppress immune reactions. Binding of HLA-G with KIR results in inhibition of cytokine production by NK cells, inhibiting their capacity to perform cell lysis
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Card 2

Front

What cardiovascular changes happen during pregnancy?

Back

Increase cardiac output (heart rate + stroke volume) & decrease in peripheral resistance (relaxed vascular tone, rise blood vol) -> overall fall in BP (lowest mid pregnancy, normal by term), decreased venous return (uterus can occlude vena cava)

Card 3

Front

What haematological changes happen during pregnancy?

Back

Preview of the front of card 3

Card 4

Front

What iron & B vitamin changes happen during pregnancy?

Back

Preview of the front of card 4

Card 5

Front

What anatomical & physiological renal changes happen during pregnancy?

Back

Preview of the front of card 5
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