Name a class of medications that are contraindicated in pregnancy.

ACE inhibitors are a class of medications that are contraindicated in pregnancy due to their potential to cause serious harm to the developing fetus. These medications work by blocking the angiotensin-converting enzyme, which is crucial for the renin-angiotensin-aldosterone system that regulates blood pressure. When taken during pregnancy, particularly in the second and third trimesters, ACE inhibitors can lead to adverse outcomes such as fetal renal failure, oligohydramnios (low amniotic fluid), and even fetal death. They are associated with the development of fetal abnormalities and growth restrictions, making their use highly discouraged in pregnant individuals.

Other classes of medications, such as beta-blockers and calcium channel blockers, may have specific uses in pregnancy under careful medical supervision, although they also carry risks and require caution. Antibiotics vary widely in their safety profiles; some are safe in pregnancy while others are not. Thus, ACE inhibitors stand out as particularly contraindicated due to the significant risks they pose to fetal development.