Some effects of maternal pethidine administration on the newborn

The effects of maternal pethidine administration (100 mg intramuscularly) were investigated in 150 infants at 1-2 h after birth, 95 infants whose mothers had not received pethidine served as a control group. Pethidine administration showed no effect on pH or PCO2 of cord blood and neonatal arterial blood at 1-2 h after birth if the time interval between pethidine administration and delivery was less than or equal to 1 h. However, when the interval was greater than 1 h: umbilical vein blood PCO2 was higher; neonatal arterial blood PCO2 was higher; neonatal baseline heart rate was higher, although long-term variability was similar; the percentage time spent crying was considerably reduced compared with the corresponding values in the control group. The long-term effects of pethidine are unknown but the adverse neonatal factors particularly if the time interval between administration of the drug and delivery is greater than 1 h should be kept in mind.