Preterm birth is still the major cause of neonatal mortality and morbidity despite major improvements in neonatal care in the developed countries. Among survivors, the risk of severe consequences is inversely related to the gestational age at delivery. Appropriate antenatal intervention should delay delivery long enough to reduce perinatal consequences related to prematurity. Efficacy of tocolysis varies with gestational age and by the underlying cause of the preterm labour. In this paper we evaluate the use of not steroid anti-inflammatory drugs (NSAIDs) and other tocolytic agents in premature labor as optimal acute first-line treatment. We'll then discuss the use of medical therapy in order to delay delivery beyond 48 hours in selected cases. In a ongoing prospectic randomised trial we consider the association Atosiban - Progesterone to treat spontaneous preterm labor. Our preliminary data suggest that vaginal administration of Progesterone after arrest of uterine activity by atosiban administration could be able to prolong pregnancy in subjects with short cervix.