Naloxone reversal of mild neurobehavioral depression in normal newborn infants after routine obstetric analgesia.

To investigate the presence of subtle narcotic depression following maternal narcotic analgesia, we have evaluated the effects of naloxone versus placebo in a double-blind parallel group study in 43 normal term newborn infants whose mothers had received routine narcotic analgesia within six hours prior to delivery. Infants were given either an intramuscular injection of 20 microgram/kg naloxone or 0.20 ml/kg placebo after determination of the one-minute Apgar score, and the following measurements were compared: Apgar scores at one and five minutes, capillary blood gas values at one, 60, 120, and 240 minutes, and neurobehavioral assessments at one, 4, and 24 hours. No adverse effects from naloxone were observed. Neither Apgar scores nor capillary blood gas determinations differed significantly between the two groups. Response to sound was significantly higher in the naloxone group at 24 hours. The alertness score was significantly higher for the naloxone group at one and four hours; the general assessment score for the naloxone group was significantly higher at four and 24 hours. Average scores of naloxone and placebo groups were also different at four and 24 hours of age. These data demonstrate that maternal narcotic analgesia may produce subtle changes in alertness and general behavior not reflected by Apgar scores or respiratory status, potentially reversible by administration of naloxone shortly following delivery.