Serum Cholinesterase Activity During Pregnancy, Labor and the Puerperium

Abstract

In 30 healthy obstetrical patients, determinations of serum cholinesterase were performed during labor, 1 day and 3 days postpartum. Ten patients were studied late in pregnancy and 6 weeks postpartum. Compared to nonpregnant values as determined 6 weeks postpartum, there was a 27.7% reduction of enzyme activity during late pregnancy, a 15.6% decrease during labor, a 24.6% decrease 1 day postpartum, and a 32.3% decrease 2 days later. Compared to values during labor, over 90% had falls of cholinesterase activity 3 days postpartum. Low cholinesterase values (below 55 units/ml) were found in 10% of patients in late pregnancy and during labor, in 20% of patients one day postpartum, and in 60% of patients 2 days later. A case is presented of prolonged paralysis following the use of 400 mg succinyl-choline during cesarean section. Subsequent studies disclosed abnormally low serum cholinesterase activity, but a qualitatively normal enzyme.