Uterine relaxants, also called tocolytics, are used to treat preterm labor. Preterm labor occurs before the thirty-seventh week of pregnancy. Uterine relaxants are generally used between the twentieth and thirty-seventh week of pregnancy. They work by relaxing the smooth muscles of the uterus and preventing contractions and labor induction. This action increases the chances of fetal survival.1 Other treatment of preterm labor includes bedrest, hydration, and sedation. Although Terbutaline (Brethine) is prescribed to treat preterm labor, its use is considered off-label as the United States drug labeling does not recognize it for this use.¹ Magnesium sulfate can be used to treat preterm labor but is used primarily as an anticonvulsant in pregnancy-induced hypertension. Note, nifedipine, a calcium channel blocker, and the nonsteroidal anti-inflammatory drug indomethacin may be used to treat preterm labor.