Which medication class is contraindicated in pregnancy due to potential harm to the fetus?

The medication class that is contraindicated in pregnancy due to potential harm to the fetus is ACE inhibitors. ACE inhibitors, such as lisinopril and enalapril, are known to be teratogenic, particularly during the second and third trimesters of pregnancy. They can disrupt fetal renal function and lead to complications such as oligohydramnios, fetal lung hypoplasia, and facial deformities, including the characteristic "potter's facies." The risk of these adverse effects makes the use of ACE inhibitors highly discouraged in pregnant patients.

In contrast, while aminoglycosides can pose risks such as ototoxicity or nephrotoxicity, they are not typically categorized as contraindicated in pregnancy, especially when the potential benefits outweigh the risks. Calcium channel blockers have not been shown to have significant teratogenic effects and may be used in certain pregnancy-related conditions. Statins, although they are contraindicated due to potential risks to fetal development, are specifically associated with certain congenital malformations and impaired fetal development. Therefore, of the medication classes listed, ACE inhibitors have the most well-documented contraindications during pregnancy, making them the correct answer.