Prematurity is an important cause of perinatal mortality and morbidity. The incidence is not decreasing, despite the efforts of prevention. Few interventions were demonstrated effective to decrease the risk of preterm birth. We are currently conducting two randomized trials including women with preterm labor. The objective of one trial is to evaluate a psychotherapeutic intervention. The other trial is multicentric to evaluate vaginal progesterone. We hope that these two trials will provide us with valid evidence on the effectiveness of these interventions to decrease the risk of preterm delivery and of neonatal consequences.