OBJECTIVES: Preterm birth (PTB) is a major cause of neonatal morbidity and mortality worldwide. Effective use of tocolytic agents may improve perinatal outcomes. This study aims to compare the effectiveness and safety of nifedipine and magnesium sulfate in the treatment of PTB. DESIGN: A systematic review and meta-analysis. DATA SOURCES: China National Knowledge Infrastructure, China Science and Technology Journal Database, WanFang, PubMed, Embase, Web of Science and Cochrane were searched from inception to 1 December 2024. ELIGIBILITY CRITERIA: We included randomised controlled trials (RCTs) and cohort studies that compare the efficacy and safety of magnesium sulfate versus nifedipine in treating PTB. DATA EXTRACTION AND SYNTHESIS: Two researchers independently screened studies and extracted data. Risk of bias was assessed using the Cochrane risk-of-bias assessment tool for RCTs and the modified Newcastle-Ottawa Scale for non-randomised studies. Meta-analysis was conducted using Review Manager V.5.4. RESULTS: In all, 50 articles were included in this review, comprising 6072 cases (n=3014 for the magnesium sulfate group
n=3058 for the nifedipine group). Compared with the magnesium sulfate group, the nifedipine group was more favourable in terms of time to onset of action and prolongation of days of gestation, as well as higher neonatal 1 min Apgar scores. The use of magnesium sulfate was associated with a higher incidence of maternal side effects, specifically tachycardia, flushing, palpitations, dizziness and nausea. In addition, the magnesium sulfate group also showed a higher incidence of neonatal respiratory distress syndrome than the nifedipine group. CONCLUSION: Compared with magnesium sulfate, nifedipine is more effective with a faster onset of action and a longer prolonging pregnancy. Additionally, nifedipine may be safer for fewer maternal side effects and better neonatal outcomes. Further studies are needed to confirm the long-term safety and efficacy of these treatments.