Prevention of neonatal mortality linked to prematurity may be achieved by treating preterm labor, thus allowing fetal lungs to spontaneously develop, or by administering drugs able to enhance pulmonary maturation. The methylxantine derivative aminophylline has been reported to reduce uterine contractility and increase the concentrations of saturated phosphatidylcholine in fetal lungs. Its effectiveness in treating preterm labor and preventing respiratory distress syndrome (RDS) has been evaluated in comparison to the widely used drug ritodrine. In 39 pregnant women with preterm labor the efficacy of aminophylline and ritodrine in delaying the delivery seemed similar. However, while two of the babies born from ritodrine treated mothers died because of RDS, all babies born from aminophylline-treated mothers survived. These data might then confirm the effectiveness of aminophylline treatment to prevent RDS.