Intramuscular 17 α-hydroxyprogesterone caproate (Makena(®)), a synthetic progestin, is indicated to reduce the risk of preterm birth in women with a singleton pregnancy who have a history of a singleton spontaneous preterm birth. Makena(®) reduces the risk of preterm birth in this patient population, and is associated with improvements in certain fetal/neonatal outcomes. The use of this US FDA-approved formulation of 17 α-hydroxyprogesterone caproate reduces the inherent risks associated with the use of pharmacy-compounded formulations of the drug.