The Effects of Hot Showers and Intravenous Injection of Hyoscine on the Pain Intensity and Duration of Active Phase of Labor in Nulliparous Women: A Randomized Clinical Trial

Abstract

Abstract: Background: Parturition is a painful process and one of midwives' duties is reducing pain in parturition. Thus, decreasing of pain and duration of labor stages always has been considered in health systems. Hot shower and intravenous injection of hyoscine are applied to reduce duration of labor stages by obstetricians and some midwives. But their effects have not been completely assessed. This research aimed to assess the effect of hot shower and intravenous injection of hyoscine on the pain and duration of active labor phase (primary outcomes) and childbirth experience, the duration of the second and third stages of labor, childbirth satisfaction, frequency of oxytocin consumption and adverse events (secondary outcomes) in nulliparous women. Methods: In this single-blind randomized controlled clinical trial, 126 nulliparous pregnant women were assigned into 3 groups with 54 participants in each group through block randomization. The first intervention group received hyoscine, the second intervention group received hot shower, and the control group received routine care. Pain intensity was measured once every hour during active phase of labor by Visual Analogue Scale (VAS) and duration of active phase, second and third stages of labor was recorded by minutes. The childbirth experience questionnaire was completed by participants 12 to 24 hours after delivery. ANCOVA, one-way analysis of variance, Kruskal–Wallis and Chi-square tests were used for analyzing data. Findings: Among three groups, there was no statistically significant difference in terms of socio-demographic characteristics and baseline pain severity (P>0.05). According to general linear model by adjusting the baseline values, average pain intensity in hyoscine group (adjusted mean difference= -0.6; 95% Confidence Interval = -1.2 to -0.1) and hot shower group (-1.1; -1.6 to -0.5) was significantly less than control group. The mean (Standard Deviation) duration of active phase of labor in hyoscine group was 221.2 (87.2) minute, in hot shower group was 201.9 (147.4) minute that was significantly lower than the control group 312.6 (198.0) minutes (P<0.001). According to one way ANOVA and Tukey post-hoc test, the mean score of childbirth experience compared with routine care group in the group hyoscine (mean difference: 5; 95% Confidence Interval: 1.0 to 8.9) and hot shower (mean difference= 3.3; 95% Confidence Interval= 6.0 to 7.2) was significantly more (P<0.05). There was no significant difference between groups in terms of pain intensity, duration of the active phase of labor and childbirth experience (p>0.05). The mean (SD) duration of the second stage of labor in hyoscine group was 47.0 (38.0), 49.1 (35.4) for hot showers group and 62.6 (46.5) minutes for the control group that there was no significant difference between groups (P=0.159). The mean (SD) duration of the third stage of labor in hyoscine group was 9.5 (4.3), 10.5 (5.2) for hot showers group and in the control group 11.0 (5.2) minutes that there was no significant difference between groups (P=0.457). In terms of childbirth satisfaction and frequency of oxytocin use, there was no significant difference between groups (P >0.05). Conclusion: Use of non- pharmacological method of hot shower reduces the pain and duration of parturition and improves the childbirth experience. Thus, using of this method is recommended to mothers