Effect of topical magnesium sulfate on labor duration and childbirth experience: a randomized controlled trial

Abstract

Abstract Background: Magnesium sulfate is used topically to reduce duration of labor in some regions of the country. However, there is insufficient evidence about its effectiveness. This study aimed to determine whether topical magnesium sulfate reduces labor duration and improves childbirth experience (primary outcomes). Methods: In this randomized controlled trial, the participants were 98 women with low-risk, singleton, and full-term pregnancies hospitalized in one of Iran’s teaching hospitals. They were randomly assigned to an intervention group (receiving 50% magnesium sulfate) or a control group (receiving distilled water) stratified by parity (nulliparous/parous) and type of onset of labor (spontaneous/induced). The participants, interventionists, and data collectors were blinded. During the vaginal examination at the beginning of the active phase of labor, 10 mL of magnesium sulfate or distilled water was poured on the cervix of uterine. Data were collected by the researcher under continuous monitoring up to two hours after delivery and with follow-up 4-5 weeks after delivery. The Childbirth Experience Questionnaire 2.0 was used to examine childbirth experience. Results: The participants were recruited from December 2021 to December 2022. 33% were primiparous women and 37% had an induced labor. Of the 49 women assigned to each group, three and seven women in the intervention and control groups, respectively, were excluded from the analysis for outcome of the labor duration due to emergency cesarean section, and one and two women for the childbirth experience due to loss to follow-up. In the intervention group compared to the control group, the mean duration of the intervention until delivery was significantly shorter (1.5 vs. 2.9 hours; MD -1.3, 95% CI [-1.9 to -0.7]) and the childbirth experience score was higher (3.1 vs. 2.2, MD 0.8; 95% CI [0.6 to 1.1]). Conclusion: According to the results of this trial, pouring 10 mL of 50% magnesium sulfate into the cervix at the beginning of the active phase of labor reduces labor duration and improves the childbirth experience. Considering such promising results, further studies in different settings are suggested to provide high-certainty evidence in this field. Trial registration: Ethics Committee of Tabriz University of Medical Sciences: IR.TBZMED.REC. 1400.726. Iranian Registry of Clinical Trials: IRCT20100414003706N40 Registration date: November 21, 2021 (https://www.irct.ir/trial/58323)