Background Labor progression and pain management are critical challenges in obstetric care. While intravenous dexamethasone has shown efficacy in accelerating labor, its systemic risks limit its use. Intravaginal magnesium sulfate offers a potential alternative, but comparative studies are lacking. This study aimed to compare the efficacy and safety of these interventions for labor acceleration.

Methods A Bayesian adaptive randomized controlled trial was conducted with 150 primiparous women in the latent phase of labor, allocated to three groups: intravaginal magnesium sulfate (50%, 10cc), intravenous dexamethasone (8mg), and routine care. Primary outcomes included labor duration and Bishop score changes, while secondary outcomes assessed neonatal Apgar scores and maternal adverse effects. Bayesian and frequentist analyses were employed, with adjustments for baseline imbalances.

Results Magnesium sulfate significantly reduced latent phase duration by 3.0 hours (95% CrI: 2.2 to 3.9) and active phase duration by 1.99 hours (1.03 to 2.99), outperforming dexamethasone (1.8 and 1.09 hours, respectively). Both interventions achieved comparable peak Bishop score improvements at 6 hours (+3.06 vs. +3.05 points). Magnesium sulfate demonstrated superior safety, avoiding systemic risks associated with dexamethasone.

Conclusions This study suggests intravaginal magnesium sulfate may be preferable to dexamethasone for labor acceleration, offering comparable efficacy with potentially fewer systemic risks. While both treatments are effective, magnesium sulfate could be considered as a first-line option, with dexamethasone reserved for specific cases.

The authors have declared no competing interest.

IRCT74207

This study did not receive any funding

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The Ethics Committee/IRB of Alborz University of Medical Sciences (ABZUMS), Kamali Hospital, Karaj, Iran, gave ethical approval for this work (approval code: IR.ABZUMS.REC.1403.076). Written informed consent was obtained from all participants.

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