Final answer:
ACE inhibitors cause fetal malformations by affecting the development of the fetal cardiovascular system, leading to fetal renal failure, oligohydramnios, pulmonary hypoplasia, limb contractures, and fetal cranial bone abnormalities.
Step-by-step explanation:
ACE inhibitors (ACEi) are known to cause fetal malformations by affecting the development of the fetal cardiovascular system. Specifically, these medications can lead to fetal renal failure and oligohydramnios, which is a condition characterized by a deficiency in amniotic fluid. This deficit in amniotic fluid can cause pulmonary hypoplasia, where the baby’s lungs do not develop properly, and limb contractures, which are abnormalities in the limbs. Additionally, fetal cranial bone abnormalities have been associated with the use of ACE inhibitors during pregnancy. The mechanism involves the role of angiotensin II, a potent vasoconstrictor which increases blood pressure. When ACE inhibitors are taken, they prevent the conversion of angiotensin I into angiotensin II, leading to changes in fetal blood flow and kidney function that can harm the developing fetus.