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

Document Type : Original Article


1 Lecturer of Midwifery, Faculty of Nursing and Midwifery, Mashhad University of Medical sciences, Mashhad, Iran.

2 Lecturer of Nursing, Faculty of Nursing and Midwifery, Birjand University of Medical sciences, Birjand, Iran.

3 . Associate Professor of Obstetrics and Gynecology, Women’s Health Research Center, Faculty of Medicine, Mashhad University of Medical sciences, Mashhad, Iran.

4 B.Sc. of Midwifery, Omol Banin Hospital, Mashhad University of Medical sciences, Mashhad, Iran.


Introduction: 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.
Methods: 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.
Results: 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).
Conclusion: It seems that Promethazine can be used as an effective drug to shorten the length of laboring in comparison with Hyoscine N-butyl bromide.


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