Transient plasma cholinesterase deficiency in preterm infants.

Plasma cholinesterase (ChE) activity was determined shortly after birth in 39 healthy preterm and 20 term infants using a commercially available screening assay. 40 samples of adult blood were analyzed for comparison purposes. There were no statistically significant differences in abnormally low enzyme levels in preterm or term infants and adults. Furthermore, in the preterm infants, ChE activity could not be correlated to gestational age, sex or race. Initially low ChE levels rose to normal adult levels within 2 weeks in all but 2 preterm infants. When muscle relaxant use is deemed necessary in hospitalized preterm infants, measurement of enzyme activity or use of drugs other than succinylcholine may be indicated on the basis of transient ChE deficiency.