Plasma cholinesterase in pregnancy--effect of enzyme activity on the duration of action of succinylcholine.

The duration of action of succinylcholine, 1 mg/kg and plasma cholinesterase activity were compared in 25 pregnant women undergoing cesarean section and 25 non-pregnant women undergoing elective surgery. Neuromuscular activity was assessed by observation of thumb adduction, following stimulation of the ulnar nerve at the wrist. The duration of action of succinylcholine was significantly longer and enzyme levels significantly lower in the pregnant women. Monitoring of neuromuscular function is recommended when succinylcholine is used in pregnant women.