Final answer:
Terbutaline and Ritodrine are beta-adrenergic agonists used off-label to manage preterm labor in pregnancy, where they work by relaxing uterine muscles to delay childbirth.
Step-by-step explanation:
Terbutaline and Ritodrine are medications that have been used in pregnancy to help manage preterm labor. These drugs are classified as beta-adrenergic agonists, which can relax smooth muscle, including the muscles in the uterus, thereby reducing uterine activity and delaying childbirth. Although primarily used for conditions like high blood pressure, chest pain (angina), and certain heart rhythm disorders, in the obstetric context, the focus is on their ability to prevent or slow down labor contractions. It is important to note that the use of these medications can have side effects and should only be used under the supervision of a healthcare provider.