- ACE inhibitors such as lisinopril are generally avoided in pregnancy, and clinicians usually switch to a pregnancy-appropriate blood pressure medicine, but that switch should be made by your prescriber, not on your own.
- The main documented concerns come from use in the second and third trimesters, including low amniotic fluid and effects on the baby's kidneys, skull, lungs, and growth.
- First-trimester data are more reassuring, with most studies not showing a clear increase in birth defects, though this is still discussed individually.
- Untreated high blood pressure in pregnancy carries serious risks of its own, so the goal is to keep treating it with a safer medicine, not to stop treatment.
- Do not stop lisinopril abruptly on your own; contact your prescriber and OB urgently so blood pressure stays controlled during the change.
- The old FDA pregnancy letter categories have been retired; questions about a specific exposure can go to MotherToBaby at 1-866-626-6847.
If you take lisinopril for blood pressure and you are pregnant or planning to be, this is an important medicine to talk about with your clinician soon, rather than to decide about alone. Lisinopril belongs to a drug family that health authorities generally advise avoiding in pregnancy. At the same time, high blood pressure itself needs to be controlled, so the answer is almost never “just stop.” This article gathers what leading U.S. sources say so you can have that conversation well informed. It is general education only and is not a substitute for medical advice.
What lisinopril is and what it treats
Lisinopril is an angiotensin-converting enzyme inhibitor, usually shortened to ACE inhibitor. Others in the family include enalapril, ramipril, and benazepril. These medicines relax blood vessels to lower blood pressure and are also used to protect the heart and kidneys in certain conditions. The same hormone system they act on, the renin-angiotensin system, plays an important role in the baby’s kidney development and in maintaining amniotic fluid, which is a large part of why timing in pregnancy matters so much here.
What the guidance says by trimester
The consistent message across sources is that ACE inhibitors deserve particular caution as pregnancy progresses, and that most people on them are switched to a different blood pressure medicine.
Second and third trimesters
This is where the clearest concerns lie. MotherToBaby, a service of the non-profit Organization of Teratology Information Specialists, reports that ACE inhibitors such as lisinopril should be avoided in the second and third trimesters. Used in this window, they can reduce the baby’s urine output and lead to low levels of amniotic fluid, the fluid that cushions the baby. Low fluid can in turn contribute to poor development of the lungs, restricted growth, effects on the developing skull bones, and problems with the developing kidneys. MotherToBaby also notes that ACE inhibitors can cause low blood pressure and kidney problems in the newborn, and in severe cases the outcomes can be very serious. Because of this, clinicians treat continued ACE-inhibitor use in later pregnancy as something to avoid whenever an alternative is possible.
First trimester
The picture earlier in pregnancy is more reassuring. MotherToBaby reports that most studies have not found a clear increase in birth defects with first-trimester use of ACE inhibitors. This is genuinely helpful context if you took lisinopril before you knew you were pregnant. It does not mean the medicine is simply continued, though, because the later-pregnancy concerns still apply, so the usual plan is to move to a pregnancy-appropriate option early.
What clinicians usually do instead
Because high blood pressure still needs treatment, the standard approach is to switch, not to stop. The American College of Obstetricians and Gynecologists (ACOG) describes medicines such as labetalol and nifedipine as commonly used, better-studied choices for blood pressure in pregnancy, and often methyldopa as well. ACOG also recommends low-dose aspirin for many pregnant people with chronic hypertension to help lower the chance of preeclampsia. The key point is that this switch is a medical decision your prescriber makes with you, ideally before pregnancy or as early as possible, so your blood pressure stays controlled throughout.
The other side: untreated high blood pressure is not safe either
It would be a mistake to read “avoid lisinopril” as “avoid treatment.” Uncontrolled high blood pressure in pregnancy carries real risks for both parent and baby, including preeclampsia, problems with the placenta, restricted fetal growth, preterm birth, and serious complications for the parent. The goal your care team will aim for is steady blood pressure control using a medicine better suited to pregnancy, not an untreated stretch of high readings. That is exactly why stopping on your own is the wrong move.
Do not stop abruptly on your own
If you are pregnant and taking lisinopril, the safest step is to contact your prescriber and OB promptly, ideally right away, rather than stopping the tablets on your own. Suddenly leaving high blood pressure untreated can be dangerous, and your clinician will want to bridge you to a suitable alternative so control is not lost during the change. None of this is a reason to feel ashamed if you have been taking lisinopril; many people are on it for good reasons and simply need a planned switch. The action to take is a prompt phone call, not a panicked stop.
A note on the old letter categories
Older references sometimes assigned ACE inhibitors an FDA pregnancy “category,” such as C or D. That letter system has been retired. U.S. drug labels now use a narrative format under the Pregnancy and Lactation Labeling Rule that describes what is actually known. If you find an old letter grade for lisinopril, treat it as out of date and ask your clinician for the current guidance.
Breastfeeding
MotherToBaby notes that whether breastfeeding is compatible depends on the specific medicine, and that some blood pressure medicines are considered acceptable while nursing. Because this is drug-specific, confirm the plan for your situation with your clinician, and you can also contact MotherToBaby for information on a particular medicine.
When to call your OB or a specialist
Reach out to your obstetric provider and prescriber if you are pregnant or planning pregnancy and take lisinopril or another ACE inhibitor, and promptly if you have already been taking it in pregnancy. Seek urgent care for warning signs of a blood pressure emergency, such as a severe headache, vision changes, chest pain, shortness of breath, or swelling that comes on suddenly. For questions about a specific exposure, call MotherToBaby at 1-866-626-6847, a free service that answers questions about medicines in pregnancy and breastfeeding.
Frequently asked questions
Is lisinopril safe to take while pregnant? It is generally avoided, especially after the first trimester, because of documented risks to the baby’s kidneys, amniotic fluid, and development. Most people are switched to a pregnancy-appropriate blood pressure medicine by their prescriber.
I took lisinopril before I knew I was pregnant. Should I worry? Try not to panic. MotherToBaby reports that most studies have not found a clear increase in birth defects with first-trimester use. Contact your OB promptly so your medicine can be reviewed and switched.
Should I just stop taking it? Not on your own. Stopping can leave your blood pressure dangerously uncontrolled. Contact your prescriber urgently so they can move you to a safer option without losing control.
What will my doctor switch me to? That is individualized, but ACOG describes options such as labetalol, nifedipine, or methyldopa as commonly used in pregnancy. Your prescriber will choose based on your history.
Why is later pregnancy the bigger concern? In the second and third trimesters, ACE inhibitors can lower the baby’s urine output and amniotic fluid and affect the developing kidneys, lungs, skull, and growth, which is why they are avoided then.
Can I take lisinopril while breastfeeding? It depends on the specific medicine. Some blood pressure medicines are considered compatible with breastfeeding. Confirm with your clinician or MotherToBaby for your particular drug.
This article is general education, not medical advice, and must not be used to start, stop, adjust, or taper any medication on your own. Suddenly stopping some medicines can be dangerous. Always work with the prescriber who manages your care. In an emergency call 911; for mental-health crisis call or text 988.
Sources
- MotherToBaby (Organization of Teratology Information Specialists) — Lisinopril fact sheet and ACE Inhibitors fact sheet.
- American College of Obstetricians and Gynecologists (ACOG) — guidance on chronic hypertension in pregnancy, including commonly used antihypertensives and low-dose aspirin for preeclampsia prevention.