- Maternal physiology
- CVS
- Plasma volume increases 45%
- Increase TBW
- Red cell mass increases 20% (Epo)
- Hb falls during 3rd trimester due to dilution
- WCC increases post delivery
- SVR decreases by 20%
- SBP and DBP decrease so there is compensatory increase in HR
- SV increases by 25%, co increases by up to 50% during labour
- Aortocaval compression
- Respiratory
- Anatomical
- Capillary engorgement
- Oedema of the upper airway
- Diaphragm moves cranially
- 20% reduction in FRC
- Inc chest diameter, large breasts
- Airway closure in 50% if supine
- Physiological
- Bronchial smooth muscle relaxation
- Increased RR
- Fall in PaCO₂
- High CO₂ production
- Coagulation
- Hypercoagulable state
- All clotting factors except XI & XIII increase
- Low platelets due to high turnover (but inc production)
- Endocrine
- Insulin production rises and there is increased resistance
- Higher than normal blood glucose in response to carbohydrate load to facilitate placental glucose transfer
- GIT
- Increased IAP
- Reduced lower oesophageal sphincter tone
- Increased gastric volume and delayed emptying in labour only
- Hepatic
- LDH, AST, ALT, GGT are all high
- PCE falls by 25%
- Acid-base
- Resp alkalosis
- ODC moves to left but high 2,3-DPG has an opposite effect
- Renal
- RBF and GFR increase
- Reduced absorption of glucose
- Increase in Vd
- CEACCP
Link:ceaccp.oxfordjournals.org/content/3/3/65.full.pdf