This method involves the use of an "alert" programmed into electronic medical records, to prompt doctors to prescribe progesterone to women at risk of preterm birth. This study is a randomized controlled trial that will assess the feasibility of using this "alert", by randomly assigning 8 clinics to either use this alert, or to provide their usual prenatal care. The investigators will then study whether the alert improved prescription of progesterone, and examine neonatal outcomes such as preterm birth and birth weight. Care providers will be asked for their feedback and thoughts about the alert, through questionnaires and structured interviews.