Effect of intrapartum meperidine on behavior of 3- to 12-month-old infant rhesus monkeys.

Potential long-term effects of intrapartum meperidine were studied in rhesus monkey infants whose dams received 0, 2, or 3 mg/kg meperidine, i.v., during labor (n = 5, 5, 3). Spontaneous behavior and cognitive performance were evaluated at 3-12 months of age. Observation of spontaneous behaviors indicated less age-related increase in quiet activities in drug-exposed infants. In the discrimination reversal test, drug-exposed infants had more balks (p = 0.008) and fewer correct choices (p = 0.008) during initial phases of the first reversal. Due to sex differences in the delayed alternation test, evaluation of drug effects on short-term memory was not possible. In the continuous performance test, drug-exposed infants performed better (NS) and had fewer omission errors (p = 0.034) during the second half of the test period. These initial findings suggest that short-term opiate exposure during labor can alter later behavior of infant monkeys.