Pregnancy Physiology Flashcards
1
Q
list the adaptations of the CVS to pregnancy
A
- significant changes occur early in first trimester
- increased circulating blood volumg + 50-70% of non-pregnant
- systemic vascular resistance falls, maximal at 20-32 weeks
- increased blood flow
- increased CO (40%), stroke volume increases
- increased heart rate
- in supine position, 25% reduction in CO
- increased oxygen consumption
2
Q
intrapartum CVS changes
A
- autotransfusion of contractions
- pain - increasing catecholamines
- CO increases by 10% in labour and by 80% in 1st post-delivery hr
3
Q
post-partum CVS changes
A
- return to normal by 3 mths (mostly)
- blood volume decreased by 10% 3 days post-delivery
- BP initially falls then increases again 3-7 days (pre preg levels by 6 wks)
- SVR increase over first 2 wks to 30% above delivery levels
- HR returns to pre preg over 2 weeks
- CO increases by up to 80% 1st hr post delivery then continues to fall over the next 24 weeks
4
Q
list respiratory system adaptations to pregnancy
A
- Significant increase in oxygen demand (20%)
- 40-50% increase in minute ventilation
- Increased respiratory rate
- Increased tidal volume
- Decreased functional residual capacity
- PEFR and FEV1 unchanged
- PCO2 ↓
- Acid base balance
- O2Hg dissociation curve
5
Q
list renal system adaptations to pregnancy
A
- Dramatic dilatation of the urinary collecting system – more pronounced on right
- Increased renal plasma flow – 60-80% by end of second trimester
- GFR ↑ and creatinine clearance increases by up to 50%
- Protein excretion increased
- Microscopic haematuria may be present
- 80% women develop oedema
- Glycosuria common
- Urate ↑ with increasing gestation
- Urea ↓, creatinine ↓
- UTIs
6
Q
haematological changes during pregnancy
A
- Plasma volume increases cf birthweight
- ↓ hg, hcrit, rcc
- No change MCV nor MCHC
- ↓ platelet count
- 2-3 fold increase in requirement for iron
- 10 -20 fold increase in folate requirements
- WCC increases
- Hypercoaguable
