Beta adrenergic agonists are still used as first line treatment for preterm labor in many institutions, but their side effects lead to use alternative tocolytic drugs such as calcium channel blockers. We report three cases of pulmonary edema during preterm labor associated with the use of calcium channel blocker, intravenous nicardipine, widely used for tocolysis in France. In this article, potential mechanisms of this severe complication are briefly discussed: pregnancy-induced overload, deleterious hemodynamic effects of calcium channel blockers, concomitant administration of calcium channel blockers and/or beta-agonists and finally concomitant administration of physiological saline and/or glucocorticoids. Based on our experience, we recommend avoiding the association of calcium channel blockers and beta-agonists for preterm labor. Nicardipine, if used, should be administered at an adjusted dose with electric syringe to reduce volume infusion.