RESUMO
PURPOSE: To compare the efficacy of nifedipine and fenoterol in the management of threatened preterm labor (TPL). METHODS: A randomized and multicenter study assessing the tocolytic effect of nifedipine versus fenoterol in patients admitted to the participating maternity units with a diagnosis of TPL and a cost-savings study for economic assessment. For a power of 80% and an α error equal to 0.05, 132 consecutive patients were recruited during the study period; 66 patients were assigned to each group. A χ(2) analysis and a mean differences test were performed according to variable types and survival curves per intention-to-treat. RESULTS: Demographics were similar in both groups. The latency period was similar in both groups (26.7 vs. 25.6; p = 0.3). There were no differences in the results obtained. Nifedipine failed more frequently to obtain tocolysis when used as a first-line agent (80 vs. 90%, p = 0.0001). The group treated with fenoterol showed more drug adverse events (57.8 vs. 19.0%, p = 0.0001). The economic assessment did not evidence a significant difference in terms of cost savings between groups treated with either drug. CONCLUSION: The present study failed to demonstrate either clinical or economic superiority of any of the two drugs used in TPL management. The highest failure percentage of nifedipine when used as a first-line agent should encourage further research.