7- Normal pregnancy and labour (Physiological changes in pregnancy) Flashcards
1
Q
In order to meet with the demands of pregnancy, physiological adaptations occur in the mother. These adaptations allow her to support and protect the foetus. Which systems are affected?
A
- Endocrine
- Cardiovascular
- Respiratory
- Gi
- Urinary
- haematological
2
Q
endocrine system: sex hormones
A
Oestrogen and progesterone increase during pregnancy
- Oestrogen – produced by the placenta
- Progesterone being produced by the CL and later by the placenta
3
Q
endocrine system: Progesterone
A
- Maintains pregnancy
- Prevents contraction
- Suppresses the mother immune reaction fetal antigens
4
Q
endocrine system: Progesterone
A
- Maintains pregnancy
- Prevents contraction
- Suppresses the mother immune reaction fetal antigens
5
Q
endocrine system: Progesterone
A
- Maintains pregnancy
- Prevents contraction
- Suppresses the mother immune reaction fetal antigens
6
Q
endocrine system: Progesterone
A
- Maintains pregnancy
- Prevents contraction
- Suppresses the mother immune reaction fetal antigens
6
Q
endocrine system: Progesterone
A
- Maintains pregnancy
- Prevents contraction
- Suppresses the mother immune reaction fetal antigens
6
Q
endocrine system: Progesterone
A
- Maintains pregnancy
- Prevents contraction
- Suppresses the mother immune reaction fetal antigens
7
Q
endocrine system: thyroid hormones
A
- Increased levels of oestrogen results in increase in hepatic production of thyroid binding globulin (TBG)
- therefore more T3 and T4 bind to the TBG
- therefore more TSH is released by the AP gland
- therefore freee T3 and T4 levels remain unchanged, but total T3 and T4 levels increase
8
Q
Why do levels of thyroxin need to increase?
A
- Thyroxin is essential for foetus’ neural development, however the thyroid gland doesn’t function until second trimester
- Therefore increasing T3/T4 levels in mother ensures a constant supply of thyroxin in early pregnancy
9
Q
endocrine system: anti-insulin hormones
A
During pregnancy (mainly 2nd tri) there is an increase in:
- Placental lactogen
- Prolactin- suppresses FSH and LH
- Cortisol – due to rise in ACTH
10
Q
endocrine system: anti-insulin hormones affect on glycaemic control
A
- Therefore insulin resistance increases and therefor peripheral uptake of glucose decreases
- Glucose levels in blood increases ensuring continuous supply of glucose for foetus
11
Q
endocrine system: why is ketoacidosis a risk due to insulin resistance cause by anti-insulin hormones?
A
- The mother switches to an alternative source of energy which is provided by lipids.
- The increase in lipolysis means that there is an increase in free fatty acids in the plasma which provide substrate for maternal metabolism.
- The breakdown of lipids can result in ketogenesis
12
Q
Gestational diabetes mellitus
A
- normally as insulin resistance which occurs in pregnancy is counteracted by increasing insulin production
- In women with gestational diabetes, this compensatory oncrease does not occur- therefore hyperglycaemia
- RF: age, high BMI, family history of T2DM, smoking
13
Q
endocrine system: PTH and calcium
A
- Calcium for the growth of the babies bones used up
- Stimulation of Parathyroid
- Causes increase in PTH :
o Increase 25(OH) D
o Increase alpha hydroxylase which activates 25(OH) D to vitamin D -> increases Ca and phosphorus absorption - Mother needs to eat food rich in calcium
14
Q
endocrine system: other hormones affected
A
- Increased melanocyte stimulating g hormone – increased pigmentation (linea nigra and melasma)
- HCG rise , doubling every 48hours and plateauing around 8-12 weeks, then falling
15
Q
resp system: anatomical changes
A
- Expanding uterus causes upwards displacement of diaphragm
- However total lung capacity doesn’t change that much because there is also an increase in the transverse and anterior posterior diameters of the thorax
16
Q
respiratory system: why does minute ventilation rate and tidal volume increase
A
- increased metabolic rate during pregnancy- increases demand for oxygen
- Minute ventilation rate and tidal volume increases to help mother meet oxygen demand
17
Q
respiratory system: resp alkalosis
A
- Hyperventilation experienced in pregnancy due to increased CO2 production and increased respiratory drive caused by progesterone
- Hyperventilation causes respiratory alkalosis – compensated by increased renal bicarbonate excretion
18
Q
GI sytem: reflux
A
GI reflux causing heart burn, N and V
- Expanding uterus can cause upwards displacement of the stomach
- Increases intra-gastric pressure
- progesterone also causes relaxation of oesophageal sphincter
19
Q
GI system: appendix
A
- Moves to the right upper quadrant as the uterus enlarges
20
Q
GI system: Gut motility
A
- Progesterone causes smooth muscle relaxation, decreasing gut motility
- Benefit- more time for nutrient absorption
- Negatives- constipation
21
Q
GI system: structural changes
A
- Gravid uterus can displace bowel causing mechanical obstruction
22
Q
GI system: relaxation of gallbladder
A
- due to progesterone
- Biliary tract stasis- gallstones predisposition
23
GI system: ALP
ALP levels increase due to placental synthesis
24
haematological system: VTE
Increased risk of thromboembolic disease
- Increase in fibrinogen and clotting factors in the blood
- Decrease in fibrinolysis
- Progesterone causes stasis of blood occurs
- LMWHeparin only option for anticoagulation in pregnancy
25
haematological changes: dilutional anaemia
- During pregnancy, the plasma volume increases significantly, however, the red cell mass does not increase by as much
26
haematological changes: others
* Increased white blood cells
* Decreased platelet count
* Increased ESR and D-dimer
* Increased alkaline phosphatase (ALP), up to 4 times normal, due to secretion by the placenta
* Reduced albumin due to loss of proteins in the kidneys
* Calcium requirements increase, but so does gut absorption of calcium, meaning calcium levels remain stable
27
urinary system: eGFR and urea and creatinine
- Increased cardiac output during pregnancy causes an increase in renal plasma flow, which increases the GFR by about 50-60%. This would mean that there is an increase in renal excretion, so in pregnancy, the levels of urea and creatinine will be lower.
- Increased urine output – increased urinary frequency
- Loss of protein in the urine
28
urinary system: RAAS
Increased RAAS
- Increases salt and water reabsorption and retention-> increase blood volume
29
urinary system: anatomy
- Progesterone causes relaxation of the uterus (resulting in hydroureter) and relaxation of the muscles of the bladder
- Together these changes causes urinary stasis -> UTI -> pyelonephritis
- Physiological hydronephrosis due to the dilatation of ureters and collecting system
30
MSK: back pain
Change in centre of gravity
- Increased lordosis and kyphosis
- Forward flexion of neck
Stretching of abdominal muscles
- Impede posture
- Strain paraspinal muscles
31
MSK: Pelvic pain
o Increased mobility of sacroiliac joints and pubic symphysis
o Anterior tilt of pelvis
32
MSK: Pelvic pain
o Increased mobility of sacroiliac joints and pubic symphysis
o Anterior tilt of pelvis
33
MSK: Carpal tunnel
- Fluid retention can cause compression structures such as median nerve (carpal tunnel)
34
Skin adapations
35
immune system: why is the immune system weakened
Parasite- genetically different
Fetus= hemi-allograft
- Recognised by maternal immune system
36
immune system: what causes immunosuppression
- Increase in ACTH- increases steroid hormone cortisol which causes immunosuppression
- Higher attack rate and severity of certain viral pathogens i.e. varicella, flu etc
**- May improve certain autoimmune conditions**
37
Cardiovascular system: changes
* Increased blood volume
* Increased plasma volume
* Increased cardiac output, with increased stroke volume and heart rate
* Decreased peripheral vascular resistance (due to progesterone)
* Decreased blood pressure in early and middle pregnancy, returning to normal by term
38
Cardiovascular system: changes
* Increased blood volume
* Increased plasma volume
* Increased cardiac output, with increased stroke volume and heart rate
* Decreased peripheral vascular resistance (due to progesterone)
* Decreased blood pressure in early and middle pregnancy, returning to normal by term
39
cardiovascular system: varicose veins
Varicose veins can occur due to peripheral vasodilation and obstruction of the inferior vena cava by the uterus
40
cardiovascular system: what symptoms can peripheral vasodilation cause
flushing and hot sweats
