As a clinical pharmacist, you will be asked more, which blood pressure medications are safe to use during pregnancy? ✅ We avoid ACE inhibitors and ARBs because they can cause serious fetal injury or death when used during the second or third trimester.
But their effects in the first trimester are more controversial. Some evidence links ACEI use in the first trimester to fetal cardiac and CNS defects. Now new observational data suggest that using an ACEI in the first trimester may NOT increase risk of birth defects.
For now, continue to avoid an ACEI, ARB, spironolactone, eplerenone, or aliskiren during pregnancy. Consider other antihypertensive medications if women are, or may become, pregnant. Choose nifedipine ER (Epilat retard) or labetalol first. These aren't linked to significant fetal adverse outcomes. Don't jump to other CCBs, they don't have as much safety data. Avoid atenolol and lean away from beta-blockers other than labetalol, because they may impair fetal growth.
Save methyldopa for when other first-line options aren't enough. It has a long history of safety in pregnancy, but it's a weak antihypertensive and causes more fatigue and dizziness. It's okay if women continue a thiazide after becoming pregnant. But try not to start one during pregnancy due to possible hypovolemia. See our note, "Which anti-hypertensives are safe to use during pregnancy?" to find out more about the safety of BP meds in pregnancy.
REFERENCES
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Hypertension in pregnancy. Report of the American College of Obstetricians and Gynecologists’ Task Force on Hypertension in Pregnancy. Obstet Gynecol. 2013 Nov;122(5):1122-1131. Available at: https://journals.lww.com/greenjournal/Fulltext/2013/11000/Hypertension_in_Pregnancy__Executive_Summary.36.aspx
Bateman BT, Patorno E, Desai RJ, Seely EW, Mogun H, Dejene SZ, Fischer MA, Friedman AM, Hernandez-Diaz S, Huybrechts KF. Angiotensin-Converting Enzyme Inhibitors and the Risk of Congenital Malformations. Obstet Gynecol. 2017 Jan;129(1):174-184. Available at: https://journals.lww.com/greenjournal/Abstract/2017/01000/Angiotensin_Converting_Enzyme_Inhibitors_and_the.23.aspx
Seely EW, Ecker J. Chronic hypertension in pregnancy. Circulation. 2014 Mar 18;129(11):1254-61. Available at: https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.113.003904