Preterm delivery with its short-term and long-term sequealae constitutes a serious problem in terms of morbidity, disability and mortality of the newborn and cost to the society. The incidence of premature deliveries persists and according to the latest national and international reports a tendency for an increase has been observed. Therefore, besides screening programmes for the detection of vaginal infections one has to look for additional therapeutic concepts. According to previous data and recent publications, progesterone vaginally and 17alpha-hydroxyprogesterone caproate intramuscularely should be considered as possible treatment options for the prevention of preterm delivery in high-risk women, with therapy starting in the second trimester.