Final answer:
ACE inhibitors are contraindicated in pregnancy due to the risk of fetal renal failure, oligohydramnios, pulmonary hypoplasia, limb contractures, and cranial bone abnormalities, as well as in individuals with a history of angioedema due to the risk of serious allergic reactions.
Step-by-step explanation:
Two contraindications for using an ACE inhibitor (ACEI) include pregnancy and a history of angioedema associated with previous ACE inhibitor therapy. During pregnancy, the use of ACE inhibitors is contraindicated as they can cause fetal renal failure and oligohydramnios, leading to complications such as pulmonary hypoplasia and limb contractures. Additionally, fetal cranial bone abnormalities can occur. A history of angioedema, which is a serious allergic reaction, with previous ACE inhibitor therapy is another contraindication due to the risk of recurrent angioedema that can be life-threatening.