Lisinopril is not safe during pregnancy. The FDA requires a specific warning on the label stating that this drug can cause injury and even death to a developing fetus when used during the second and third trimesters. If you’re pregnant or planning to become pregnant, lisinopril should be stopped and replaced with a pregnancy-safe blood pressure medication.
Why Lisinopril Is Dangerous During Pregnancy
Lisinopril belongs to a class of blood pressure drugs called ACE inhibitors. These medications work by blocking an enzyme that tightens blood vessels, which is helpful for managing high blood pressure in adults. But that same enzyme plays a critical role in how a fetus develops, particularly in the kidneys.
The primary way lisinopril harms a fetus is by reducing blood flow to the developing kidneys. During the second and third trimesters, the fetal kidneys are actively forming and need adequate blood supply to develop normally. When lisinopril interferes with this process, the consequences can be severe: kidney failure, dangerously low blood pressure in the newborn, underdeveloped skull bones, and underdeveloped lungs. Some of these complications are fatal. In surviving infants, severely impaired kidney function can persist and progress to end-stage kidney failure.
The fetal kidneys also produce much of the amniotic fluid in later pregnancy. When lisinopril damages kidney function, amniotic fluid drops to dangerously low levels. This condition, called oligohydramnios, compounds the problem by restricting lung development and compressing the fetus.
Risks During the First Trimester
The most well-known dangers of lisinopril apply to the second and third trimesters, but first-trimester exposure carries its own risks. A study published in the New England Journal of Medicine found that infants exposed to ACE inhibitors only during the first trimester had a 2.7 times higher risk of major congenital malformations compared to infants with no exposure to blood pressure medications. This is why current guidance treats the entire pregnancy as a period to avoid ACE inhibitors, not just the later months.
Long-Term Effects on Exposed Children
Research on what happens years after in-utero exposure is still limited, but early findings are concerning. A German cohort study found that some children exposed to ACE inhibitors before birth developed high blood pressure or kidney disease years later, even when they appeared healthy at birth. In one reported case series, children who showed no signs of kidney damage as newborns went on to develop progressive kidney impairment by school age. Researchers now suspect that prenatal ACE inhibitor exposure can cause delayed harm to the kidneys and cardiovascular system that only becomes apparent in childhood.
Among children without obvious damage in the first six months of life, 1.5% were later diagnosed with high blood pressure or needed blood pressure medication, compared to 0.6% of children whose mothers took other types of blood pressure drugs. These numbers are small, but they suggest a real, measurable increase in risk.
What to Do If You’re Taking Lisinopril and Become Pregnant
If you discover you’re pregnant while taking lisinopril, stop taking it as soon as possible. Both the FDA and the UK’s Medicines and Healthcare products Regulatory Agency are clear on this point: on diagnosis of pregnancy, ACE inhibitors should be discontinued immediately and replaced with an alternative if blood pressure treatment is still needed. The earlier you switch, the lower the risk to the fetus.
This situation is common. Many women of childbearing age take lisinopril for high blood pressure and become pregnant before switching medications. The key is acting quickly. Brief first-trimester exposure, while not risk-free, is far less dangerous than continued use into the second and third trimesters, when the most severe fetal harm occurs.
Safer Blood Pressure Medications During Pregnancy
Several blood pressure medications have well-established safety profiles in pregnancy. The preferred options include:
- Labetalol: the most commonly recommended first-line choice, as it preserves blood flow to the placenta better than other options
- Nifedipine: a calcium channel blocker widely used in pregnancy
- Methyldopa: one of the oldest blood pressure drugs used in pregnancy, with decades of safety data
If you’re planning a pregnancy and currently take lisinopril, your doctor can switch you to one of these alternatives before you conceive. This avoids any first-trimester exposure entirely. For women with chronic high blood pressure, managing blood pressure during pregnancy is important, so stopping lisinopril doesn’t mean going without treatment. It means switching to a drug that controls blood pressure without harming the fetus.
Lisinopril and Breastfeeding
Unlike pregnancy, lisinopril appears to be compatible with breastfeeding. Measurements from nursing mothers taking standard doses showed that very little of the drug passes into breast milk. At a typical 10 mg daily dose, the peak concentration in milk was 0.63 micrograms per liter, which works out to just 0.06% of the mother’s dose reaching the infant. In studies of breastfeeding mothers taking lisinopril at doses ranging from 5 to 20 mg daily, no adverse effects were observed in their infants. So while lisinopril is clearly dangerous during pregnancy, it can generally be resumed safely after delivery if you choose to breastfeed.