Preterm birth has been and continues to be one of the most serious problems in Obstetrics. It is the most common cause of neonatal death, and morbidity in surviving infants. The presence of bacterial vaginosis, and other genital infections is associated with increased risk of preterm labor. Cytokines promote the release of prostaglandin, and have been implicated as cause of uterina activity. Recently, new methods of detection as transvaginal ultrasonography, and measures of cervical fetal fibronectin have been acclaimed as useful to detect the problem. Atosiban, cytokines, glyceril trinitrate, and many others agents have been proposed as treatments and are under investigation. Such drugs, will allow an effective management of preterm labor with lower side effects. Antenatal TRH administration cannot be recommended for widespread clinical use. However, the antenatal administration of corticosteroids to fetuses at risk of preterm delivery include not only a reduction in the risk of respiratory distress syndrome but also a significative reduction in intraventricular hemorrhage mortality.