[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Embryology](https://durgical.com/en/embryology/) › [Teratology and prenatal diagnosis](https://durgical.com/en/embryology/#a-teratology) › ACE inhibitors and ARBs: fetal kidney damage [Embryology](https://durgical.com/en/embryology/) · [Teratology and prenatal diagnosis](https://durgical.com/en/embryology/#a-teratology) # ACE inhibitors and ARBs: fetal kidney damage - Teratogen Some blood pressure medicines damage the fetal kidneys in the second half of pregnancy and leave too little amniotic fluid. Updated 2026-11-01 **See it in 3D:** [Kidneys](https://durgical.com/en/anatomy/kidney/) · [Parietal bones](https://durgical.com/en/anatomy/parietal-bone/) ## Key points - Second- and third-trimester fetopathy; oligohydramnios appears mostly from week 20. - Renal tubular dysgenesis, anuria and neonatal renal failure. - Oligohydramnios: pulmonary hypoplasia, joint contractures and facial deformation (Potter-like phenotype). - Skull hypoplasia (hypocalvaria), growth restriction and neonatal hypotension. - First-trimester exposure: less clear data, with no defined malformation pattern. ## What it is Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) cause a fetopathy rather than a classic embryopathy: damage appears mostly with exposure in the second and third trimesters. The fetal kidney needs angiotensin II to maintain filtration and build its tubules; without it fetal urine falls and oligohydramnios follows, with consequences for the lungs, limbs and skull. ## Key facts - Oligohydramnios can reverse if exposure ends in time. - Direct renin inhibitors share this mechanism. - Renal tubular dysgenesis also exists as a genetic disease of renin–angiotensin system genes. - Patent ductus arteriosus and fetal or neonatal death have been described. - An example of 'no stage is safe': the damage happens outside the embryonic period. ## Critical period and mechanism - Critical period: second and third trimesters, when the fetal kidney makes most of the amniotic fluid. - Angiotensin II constricts the efferent arteriole and maintains fetal glomerular filtration pressure. - Blocking it lowers filtration, disturbs tubular development and reduces fetal urine. - Lack of amniotic fluid compresses the fetus and prevents normal lung growth; poor perfusion affects the skull. ## Prevention - Planning blood pressure control with the treating professional before and during pregnancy. - Medicines in pregnancy are decided with the treating professional; they are not stopped on one's own. - Ultrasound monitoring of amniotic fluid after an exposure. ## What it does to the embryo and fetus - Oligohydramnios or anhydramnios on ultrasound; echogenic kidneys. - At birth: anuria, renal failure, hypotension. - Pulmonary hypoplasia with respiratory distress, limb contractures. - Poorly ossified skull bones, growth restriction, fetal or neonatal death. ## Memory aid ACE inhibitors in the second half: 'no angiotensin, no urine; no urine, no fluid; no fluid, no lungs'. ## Test yourself Think of the answer, then tap the question to see it. ## In which trimesters are ACE inhibitors and ARBs most harmful to the fetus? The second and third trimesters. ## Why do ACE inhibitors cause oligohydramnios? Without angiotensin II fetal glomerular filtration falls and tubular development is disturbed, so the fetus makes little urine. ## What are the consequences of that oligohydramnios? Pulmonary hypoplasia, joint contractures and facial deformation, as in the Potter sequence. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/embryology/ace-inhibitors-and-arbs-fetal-kidney-damage/) ## See it in 3D The structures of Durgical's 3D anatomy where it is found. - [Kidneys](https://durgical.com/en/anatomy/kidney/) - [Parietal bones](https://durgical.com/en/anatomy/parietal-bone/) ## Related - [Renal agenesis and the Potter sequence](https://durgical.com/en/embryology/renal-agenesis-and-the-potter-sequence/) - [Amniotic fluid: polyhydramnios and oligohydramnios](https://durgical.com/en/embryology/amniotic-fluid-polyhydramnios-and-oligohydramnios/) - [Pulmonary hypoplasia](https://durgical.com/en/embryology/pulmonary-hypoplasia/) - [Kidney: pronephros, mesonephros, metanephros and ascent](https://durgical.com/en/embryology/kidney-pronephros-mesonephros-metanephros-and-ascent/) - [Patent ductus arteriosus](https://durgical.com/en/embryology/patent-ductus-arteriosus/) - [Skull: neurocranium, viscerocranium, sutures and fontanelles](https://durgical.com/en/embryology/skull-neurocranium-viscerocranium-sutures-and-fontanelles/) - [Malformation, disruption, deformation, sequence, syndrome, association](https://durgical.com/en/embryology/malformation-disruption-deformation-sequence-syndrome-association/) ## Related conditions - [Arterial hypertension](https://durgical.com/en/conditions/arterial-hypertension/) - [Heart failure](https://durgical.com/en/conditions/heart-failure/) - [Acute kidney injury](https://durgical.com/en/conditions/acute-kidney-injury/) - [Diabetic kidney disease](https://durgical.com/en/conditions/diabetic-kidney-disease/) ## In Pharmacology - [Lisinopril](https://durgical.com/en/pharmacology/lisinopril/) - [Enalapril](https://durgical.com/en/pharmacology/enalapril/) - [Losartan](https://durgical.com/en/pharmacology/losartan/) [← All of embryology](https://durgical.com/en/embryology/) Educational content on embryonic development; not a guide to prenatal diagnosis or to medicines in pregnancy and no substitute for a health professional's advice. No doses are given. Sources: [Angiotensin‐II receptor 1 antagonist fetopathy](https://pmc.ncbi.nlm.nih.gov/articles/PMC3575949/) (PubMed Central (NCBI), 2012); Langman's Medical Embryology, 13th ed., ch. 9: Birth Defects and Prenatal Diagnosis (Wolters Kluwer, 2015). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/embryology/ace-inhibitors-and-arbs-fetal-kidney-damage/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/embryology/ace-inhibitors-and-arbs-fetal-kidney-damage/