Widely prescribed in the years 1970-1980 to prolong gestation, progesterone has regained interest after the publication of randomized trials since 10 years. In women at increased risk of preterm birth with a history of preterm delivery or late miscarriage, the use of progesterone, especially intramuscularly may reduce the incidence of spontaneous preterm birth. In contrast, in cases of preterm labor or twin pregnancies, progesterone efficacy to reduce preterm birth has not been demonstrated. In women with asymptomatic midtrimester sonographic short cervix, randomized studies show conflicting results and new studies are necessary before its widespread utilisation.