A comparative study on MgSO₄ and nifedipine as acute tocolytic agents in preterm labour

Abstract

Background: Preterm labour is a major cause of neonatal morbidity and mortality. Tocolysis helps delay delivery, allowing time for antenatal corticosteroids and in-utero transfer. Magnesium sulphate (MgSO4) and nifedipine are commonly used agents, but comparative evidence is limited. To compare the efficacy and safety of MgSO₄ and nifedipine as acute tocolytics in preterm labour.

Methods: This randomized controlled trial at a tertiary care centre - GMC Akola, enrolled 100 women between 28–34 weeks of gestation with preterm labour. Participants were randomly allocated to receive either MgSO₄ (loading dose 4 g IV, followed by 1 g/hr infusion) or oral nifedipine (10 mg every 20 min up to 3 doses, then 20 mg every 4-6 hrs for 24 hrs). Outcomes assessed were uterine quiescence, prolongation of pregnancy ≥48 hrs, maternal side effects, and neonatal outcomes.

Results: Labour was arrested in 92% of women treated with MgSO₄ and 90% with nifedipine. MgSO₄ achieved slightly higher rates of uterine quiescence and prolongation beyond 48 hrs. NICU admissions were lower with MgSO₄ (38% vs 44%), as was neonatal mortality (10% vs 14%). Side effects were mild and comparable: hot flushes/lethargy with MgSO₄ and tachycardia/headache with nifedipine. No serious adverse events occurred.

Conclusion: Both MgSO₄ and nifedipine are effective and safe tocolytic agents. MgSO₄ offers a marginal advantage in prolonging gestation and provides fetal neuroprotection, whereas nifedipine is simpler to administer and cost-effective in low-resource settings.