[Prevention of recurrent preterm birth: a comeback for progesterone?]

Progesterone has been prescribed for many years in women with preterm labor despite the lack of benefit for the fetus or neonate. The description of increased risk of intrahepatic cholestasis of pregnancy led to discontinuation of this prescription. Recently, several double-blind randomized trials have focused on the usefulness of progesterone for the prevention of recurrent preterm birth. In this review, we re-examine the pathophysiological rationale for the use of progesterone and discuss the biases and limitations of older studies, detailing two recent randomized trials which suggest use of progesterone should be revisited. Data from these trials appear to provide convincing evidence that preventive use of 17 alpha-hydroxyprogesterone administered by injections early in the course of pregnancy is effective only for women with a history of preterm delivery. This prescription could be part of a more global preventive strategy together with cervical cerclage and preventive treatment of bacterial vaginitis. During treatment, it is advisable to search for secondary hepatic effects. Conversely, there are still no data favoring the use of progesterone for preterm labor. Most preterm deliveries occurring in women without a history of preterm birth preventive use of progesterone should remain a rare indication.