Oral evening primrose oil: its effect on length of pregnancy and selected intrapartum outcomes in low-risk nulliparous women.

Evening primrose oil is widely used by many midwives to hasten cervical ripening in an effort to shorten labor and decrease the incidence of postdates pregnancies. Although its efficacy has been studied in the relief of symptoms of a number of medical conditions, its use has not been well studied, if at all, for the purpose of cervical ripening. The purpose of this study was to investigate the effect of oral evening primrose oil on the length of pregnancy and selected intrapartum outcomes in low-risk nulliparous women.