Physiology in Pregnancy Flashcards
What general changes occur during pregnancy?
- Mechanical
- Metabolism
- Fatigue – particularly early pregnancy
- Heartburn/reflux
- Oedema
- Breasts
- Thyroid
- General state of immunosuppression
- Weight gain
What changes occur to the breasts during pregnancy?
- Increased size and vascularity – warm tense and tender
- Increased pigmentation of the areola and nipple
- Secondary areola appears
What appears on the areolas?
Montgomery tubercles
When can colostrum be expressed?
From the end of the 3rd month
When do significant changes occur in the CVS?
Early in the first trimester
What changes does the CVS undergo?
- Increased circulating volume
- Systemic vascular resistance falls
- Increased blood flow
- Increased cardiac output
- Increased stroke volume
- Increased heart rate
- Increased O2 consumption
What happens to cardiac output in the supine position?
25% reduction
When does maximal systemic vascular resistance decrease occur?
20-32 weeks
By how much does cardiac output increase?
40%
Why do women experiencing pain during labour?
Increasing catecholamines
What intrapartum CS changes occur?
Auto transfusion of contractions
What happens to cardiac output during labour and post-delivery?
- Increases by 10% in labour
- Increases 80% in 1st hour post-delivery
- Continues to fall over the 1st 24 hours
What happens to blood volume post delivery?
Decreases by 10% 3 days post-delivery
What happens to blood pressure post delivery?
Falls then increases again days 3-7
What happens to SVR post delivery?
Increases over the first 2 weeks to 30% above delivery levels
What happens to heart rate post delivery?
Returns to pre-pregnancy levels over 2 weeks
When do CVS return to normal?
3 months post-partum usually
When does BP reach pre-pregnancy levels?
Usually by 6 weeks post-partum
What doesn’t change in the respiratory system with pregnancy?
PEFR and FEV1
What happens to blood gases with pregnancy?
- Decrease in PCO2
- Increase in PO2
What respiratory changes take place during pregnancy?
- Increase in oxygen demand
- Increase in minute ventilation
- Increased respiratory rate
- Increased tidal volume
- Decreased functional residual capacity
By how much does minute volume increase?
40-50%
By how much does oxygen demand increase?
20%
What may be present in the urine of pregnant women?
Glucose and microscopic haematuria
How many women develop oedema?
80%
What changes occur to the renal system?
-Dilatation of the urinary collecting system
-Increased renal plasma flow
-Increases protein excretion
Increased GFR
-Increase creatinine clearance
How much does renal plasma flow increase by, by the end of the 2nd trimester?
60-80%
How much does creatinine clearance increase by?
Up to 50%
What haematological state are pregnant women in?
Hypercoaguable
What haematological changes are there?
- Plasma volume increases
- Decreased platelet count
- Increase in iron requirement
- Increase in folate requirement
- Increase in WCC
- Decrease Hg
- Decrease haematocrit
- Decrease RCC
What does not change haematologically due to pregnancy?
No change to MCV or MCHC
By how much does the iron requirement increase?
2-3 fold
By how much does the folate requirement increase?
10-20 fold
What happens to Hg during pregnancy?
Decrease
What happens to WCC during pregnancy?
Increase
What happens to platelets during pregnancy?
Apparent decrease (change due to dilution not actual decrease)
What happens to CRP during pregnancy?
No change
What happens to ESR during pregnancy?
Increase
What happens to urea during pregnancy?
Decrease
What happens to creatinine during pregnancy?
Decrease
What happens to urate during pregnancy?
Decrease but increases with gestation
What happens to 24hr protein during pregnancy?
Increase
What happens to total protein during pregnancy?
Decrease
What happens to albumin during pregnancy?
Decrease
What happens to AST/ALT/GGT during pregnancy?
Decrease/no change
What happens to Alk phosphate during pregnancy?
Dramatic increase (due to additional production by the placenta)
What happens to bile acids during pregnancy?
No change
What happens to D dimer during pregnancy?
Increase
