Final answer:
Terbutaline and Ritodrine are contraindicated in patients with a history of preterm labor due to their potential adverse effects on the cardiovascular system.
Step-by-step explanation:
The contraindication of Terbutaline and Ritodrine is patients with a history of preterm labor. Both drugs are beta-adrenergic agonists that are used to delay premature labor contractions. However, they can have potential adverse effects on the cardiovascular system, such as increasing heart rate and blood pressure. Therefore, it is crucial to avoid using these medications in patients who have a history of preterm labor, as they may already have underlying cardiovascular issues.