Cardiovascular

Increased cardiac output

Decreased systemic vascular resistance

Aortocaval compression – hypotension called by compression of the IVC by the gravid uterus

• As early as 13-16wks, more common closer to term
• Treat with left uterine displacement

Respiratory

Decreased functional residual capacity, results in rapid desaturations

Increased minute and alveolar ventilation

Increased O2 consumption

Decreased PaCO2, increased PaO2

Increased risk of airway edema, especially during labour

GI

Delayed gastric emptying during labour leads to increased risk of aspiration

Decreased lower esophageal sphincter tone

Hematologic

Increased total blood volume

Increase fibrinogen

Decreased anticoagulant activity and impaired fibrinolysis

Decreased platelet count

Decreased cholinesterase activity

Drug Response

Decreased inhalational anesthetic requirements with increased progesterone levels during pregnancy

Decreased local anesthetic requirements