Outcomes after pethidine or diamorphine administration

Despite the common use of pethidine (PTD) and diamorphine (DMP) in providing pain control during labour, there is little evidence of their effectiveness. In addition, some studies have suggested that PTD is associated with a poor neonatal and maternal outcome. Conversely, DMP has not been reported to have any major adverse neonatal or maternal outcomes. The objective was to compare the effects of intramuscular PTD with DMP on neonatal outcome, maternal vomiting and further administration of pharmacological pain relief during labour. The study involved retrospective case note analysis of 268 women in their first pregnancy giving birth between February 1999 and May 2000: 134 receiving PTD and 134 receiving DMP as the first pharmacological pain relief in labour for a singleton vaginal delivery following an uncomplicated spontaneous labour at term. The following information was collected: neonatal Apgar score at 1 minute; neonatal resuscitation; time to first infant feed; actual and intended method of feeding; maternal vomiting; and further administration of analgesia. There were no significant differences in the two groups in respect of Apgar score of less than 7, neonatal resuscitation and time to initiate first feed. However, those women receiving PTD were significantly less likely to vomit or to require further analgesia than those receiving DMP.