Comparison of Effects of Hyoscine N-Butyl Bromide and Promethazine on Length of Active Phase of First Stage of Labor

Shortening duration of delivery without endangering mother and fetus is always highly considered by obstetric specialist and mothers. Widely use of Hyoscine N-butyl bromide and Promethazine in hospitals and limited researches with conflicting results in this regard made us investigate the efficiency of Hyoscine N-butyl bromide and Promethazine on length of active phase of the first stage of labor. A provident double-blind clinical trial was done on 188 nulliparous women. They were classified into the Hyoscine N-butyl bromide (48cases), Promethazine (45cases) and control (95 cases) groups. The samples were randomly allocated from cases who were injected 20 mg of Hyoscine N-butyl bromide, 25 mg of Promethazine IM in dilatation 3-5cm, and control group in which no medicine was used. Data analysis was performed using SPSS software version 16, t- test, chi-square and ANOVA tests. p<0.05 was considered significant. The mean duration of active phase of labor in Promethazine (5.69±3.45) was shorter than in control group (7±3.44). This difference was statistically significant (p=0.049). However duration of active phase of labor had no statistically significant difference between Hyoscine N-butyl bromide and control groups (p=0.205). However, the mean duration of active phase of labor was not statistically significant in the three groups of Hyoscine N-butyl bromide, Promethazine and control (p=0.140). It seems that Promethazine can be used as an effective drug to shorten the length of laboring in comparison with Hyoscine N-butyl bromide.