Obstetric: Normal Values
 
See also:
Definitions    Assessment    Basic Care    Destination
 
Perinatal Emergency Referral Service (PERS)
24/7 – 1300 137 650
 
Cardiovascular:
BP

Minimal change – initial decrease in 1st and 2nd trimester, 3rd normal Sytolic BP >160 and Dyastolic BP >110 is significant

  
HR ↑ by 15 – 20 bpm Normal pregnancy HR 80 to 110 /min
Cardiac output ↑ by 30 – 40% Normal volume 6 to 7 L/min during pregnancy
ECG Non specific ST changes, Q waves – III & AVF, atrial and ventricular ectopics  
SVR ↓ due to progesterone and blood volume  
Placental blood flow 600ml/minute (at term). Placenta unable to auto regulate blood flow
   
Respiratory: 
Respiratory rate

↑ by 15% (2 – 3 breaths/min)

 14 – 19 breaths/min at term
Oxygen demand ↑ by 15 - 20%  
Minute ventilation ↑ by 25 – 50% 11 – 19 L/min at term
Tidal volume ↑ by 25 – 40% 8 – 10 mls/kg at term
Arterial pH ↑ to 7.40 – 7.45  
PaO2 ↑ by 10mmHg 104 – 108mmHg at term
PaCO2 ↓ 27 – 32 mmHg  
Haematological:
Blood volume (ml)

↑ 30 – 50% Volume

 5,500mls at term
Haemoglobin (g/dL) ↓ 100 – 140 Red cell mass ↑ by 20 – 30% but is less than blood volume increase
Haematocrit (%) ↓ 32 – 42 (physiological anaemia)  
Plasma volume (ml) ↑ 30 – 50%