A COMPARISON OF PETHIDINE AND DIHYDROCODEINE FOR THE RELIEF OF LABOUR PAIN *

SUMMARY The pain‐relieving effect of pethidine 100 mg and dihydrocodeine 30 mg was investigated in 419 women during labour pain in three hospitals. A double‐blind technique was used, and the two drugs were given as the first and second injection to every other parturient woman. The analgesic effects of the drugs were rated as “good” when more than 50% pain relief was obtained, “fair” when 50% relief was obtained, and “poor” when less than 50% pain relief was achieved. The results from the three hospitals were consistent enough to warrant pooling of the data. When the total number of doses for each drug were compared, pethidine 100 mg gave “good” pain relief in 64.2% against 41.4% when dihydrocodeine 30 mg was used. When “paired doses” of the drugs were considered, the percentage of “good” pain relief afforded by pethidine was 76.5 and that by dihydrocodeine 47.1. The newborn infants were given a score according to a system suggested by V. A pgar (1953) 1 . Evaluation of the data thus obtained revealed that the scores of the infants whose mothers had received pethidine within 4 hours prior to delivery were significantly lower than the scores of those whose mothers had been given no analgesic. The number of observations on infants whose mothers had been given dihydrocodeine was small, and the differences between this group and the two others may have been due to chance.