For women with a singleton pregnancy and prior spontaneous preterm birth before 37 weeks of gestation, the following may be considered medically necessary:
Weekly injections of 17α-hydroxyprogesterone caproate, initiated between 16 and 20 weeks of gestation, and continued until 36 weeks 6 days.
Daily vaginal progesterone between 24 and 34 weeks of gestation.
For women with a singleton pregnancy and a short cervix (<20 mm), the following may be considered medically necessary: Daily vaginal progesterone initiated between 20 and 23 weeks 6 days of gestation and continued until 36 weeks 6 days. Progesterone therapy as a technique to prevent preterm delivery is considered investigational in pregnant women with other risk factors for preterm delivery, including but not limited to: twin or multiple gestations; prior episode of preterm labor in current pregnancy (ie, progesterone therapy in conjunction with tocolysis or following successful tocolysis); positive test for cervicovaginal fetal fibronectin; in conjunction with or following cervical cerclage; uterine anomaly.
