Which class of antihypertensive medication is contraindicated during pregnancy?

Angiotensin-converting enzyme (ACE) inhibitors are contraindicated during pregnancy primarily because they have been associated with significant adverse effects on fetal development. The use of ACE inhibitors during the second and third trimesters is particularly concerning, as they can lead to fetal renal dysfunction, oligohydramnios (low amniotic fluid), pulmonary hypoplasia (underdeveloped lungs), and other serious complications. The fetal risks associated with this class of medications are well-documented, leading to strong recommendations against their use in pregnant patients.

In contrast, other antihypertensive medications may be safer alternatives during pregnancy. Beta-blockers, calcium channel blockers, and alpha-2 agonists are sometimes used under medical supervision, depending on the specific clinical situation and the potential risks versus benefits for both the mother and the fetus.