ABSTRACT
Haematology: ➤ Plasma volume increases: this increases preload and VD of polar drugs. It increases by
50% by term. ➤ RBC mass increases: but plasma increases more than RBC, causing physiological
anaemia. ➤ WBC increase: to 12 × 109/L by term with a further increase to 30 × 109/L during
labour. ➤ Platelets reduce: due to consumption. ➤ Albumin decreases: this increases the free active proportion of plasma-bound drugs. ➤ Plasma oncotic pressure reduces: increases the risk of oedema. ➤ Plasma cholinesterase reduces: the effect of suxamethonium is offset by the increased
VD. ➤ Hypercoaguable: all clotting factors increase except XI and XIII. BT, PT and APTT
shortened. High risk of thromboembolic complications. ➤ CRP and ESR increase.
