[Influence of dihydroetorphine hydrochloride and tramadol on labor pain and umbilical blood gas].

Ninety primigravide were randomly allocated into three groups at the beginning of active phase of labor. Dihydroetorphine hydrochloride (DHE) was administered to group A (n = 30), tramadol to group B (n = 30), and group C (n = 30) was a blank control. Various parameters about analgesia effects, progress of labour and fetal and neonatal well-being were investigated and also umbilical artery and vein blood gases analyzing were carried out in all cases. As a result, the effective rate of pain relief in group A was 67% and in group B 63% (P > 0.05). The average time of onset of action in DHE group was 16.5 +/- 2.9 minutes which was significantly shorter than 26.1 +/- 5.4 minutes in tramadol group (P = 0.0001). There were higher rate (36.7%) of operative intervention (forceps and vaginally or cesarean section) and a higher average amount of postpartum hemorrhage in group A, as compared with the control group, but no significant difference was shown between group B and group C. No difference was found in other parameters (among the three groups duration of labour, Apgar scores of neonates, cord blood gases, etc.). The conclusion is that, both DHE and tramadol may have a good effect of pain relief in labour. The time of onset of action in DHE group is significantly shorter than that in tramadol group. Neither analgesics cause circulation and respiratory depression in the mother and neonates, but DHE may have influence on uterine contraction. To achieve an excellent pain relief by higher dosage of DHE and tramadol need further randomized investigation.