Labetalol for High Blood Pressure In Pregnancy: Benefits, Risks, and More

Hypertension (high blood pressure) during pregnancy is fairly common, affecting 8% of pregnant women ages 20 to 44 in the U.S. But there are medications that can help. Labetalol, for example, is a first-choice medication for hypertension during pregnancy. Below, we review the benefits and potential side effects, as well as what to consider before taking labetalol while breastfeeding. 

What is labetalol?

Labetalol is part of a group of medications called beta blockers. It’s FDA approved to treat hypertension in adults. It works by slowing down your heart rate and relaxing your blood vessels.

Labetalol comes as a generic oral tablet. There’s also an injectable form that is usually given in hospital settings to lower blood pressure in an emergency.

Defining hypertension during pregnancy

The phrase “hypertension during pregnancy” refers to a few different health conditions. This includes hypertension that occurs:

• Before pregnancy or within the first 20 weeks of pregnancy (chronic hypertension)

• After 20 weeks of pregnancy (gestational hypertension)

• After 20 weeks of pregnancy and is accompanied by protein in the urine (preeclampsia)

Having chronic hypertension increases your risk of developing preeclampsia. In severe cases, preeclampsia can progress to eclampsia. Eclampsia is when you experience seizures from preeclampsia.

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Labetalol during pregnancy

The American College of Obstetrics and Gynecology (ACOG) recommends treating hypertension during pregnancy if a person’s:

• Systolic (top number) blood pressure is 140 or higher

• Diastolic (bottom number) blood pressure is 90 or higher

If you fit either (or both) of the above criteria, you may be prescribed labetalol during your pregnancy. As mentioned, labetalol is a first-choice medication for treating hypertension during pregnancy.

Why is treating hypertension during pregnancy important?

Whether you’re pregnant or not, hypertension can have negative effects on your health. But during pregnancy, you have an increased blood volume, which can add to the stress on your organs. This includes your heart, kidneys, and placenta. Combined with hypertension, this stress on your body can be dangerous.

Research shows hypertension may cause several pregnancy-related risks. This includes a higher risk of:

• Preeclampsia

• Placental abruption

• Need for cesarean birth (C-section)

• Heart disease, kidney problems, and stroke

• Preterm birth or low birth weight for the baby

Getting your blood pressure checked is a routine part of every prenatal visit. If your blood pressure is elevated during a visit, you’ll likely be asked to monitor your levels at home, too. 

Good to know: If you take medication for chronic hypertension, you’ll most likely need to continue taking blood pressure medication while pregnant. But many blood pressure medications, including angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs), aren’t considered safe to take during pregnancy. So your prescriber may recommend that you switch to labetalol when you become or begin trying to become pregnant. If you’re thinking about becoming pregnant, be sure to talk with your healthcare team about the best blood pressure medication for you.

What the research says

A 2022 randomized clinical trial (RCT) looked at more than 2,400 pregnant women with mild hypertension. (This was defined as blood pressure less than 160/100 mmHg.) Half of the participants received blood pressure medication, with over 60% of those participants receiving labetalol. The other half of the participants took a placebo (a pill with no medication).

The results showed that taking blood pressure medication lowered pregnancy-related complications. This includes a decreased risk of:

• Preeclampsia

• Placental abruption

• Preterm births

• Serious complications for both the participants and their babies

Unlike many clinical trials, the participants enrolled in this study were fairly representative of the racial and ethnic makeup of pregnant women who experience hypertension in the U.S. About 50% of the study participants were Black, and 20% were Hispanic.

Labetalol dosage during pregnancy

Your prenatal care provider may prescribe you 100 mg to 200 mg of oral labetalol twice daily to start. Depending on how your blood pressure responds — and how well you’re tolerating the medication — your dosage may be increased. The maximum daily dose is 2,400 mg (taken as 800 mg doses every 8 hours).

Good to know: You’ll likely need to continue taking labetalol for some time, even after your baby is born. While gestational hypertension and preeclampsia usually resolve after a pregnancy is over, this may not happen right away. And around one-third of eclampsia cases happen in the postpartum period. Your prescriber will monitor your blood pressure and let you know how long to continue taking labetalol.

Risks of labetalol during pregnancy

Pregnant women are often excluded from clinical trials, and the early studies of labetalol were no exception. But animal studies showed labetalol didn’t cause harm to unborn fetuses, which is one of the reasons it’s a first-choice medication for hypertension during pregnancy.

Growing research involving humans has also underscored that labetalol is safe to take during pregnancy. But all medications have some risks, and these risks are especially important to consider if you’re pregnant.

Labetalol side effects

Common labetalol side effects include dizziness, slow heart rate, fatigue, and low blood pressure (hypotension). (These are risks whether you’re pregnant or not.) These side effects often improve over time as your body adjusts to the medication. To avoid falls caused by dizziness or hypotension, be extra careful with your movements after starting treatment with labetalol (or after a dosage increase).

More serious side effects, like severe liver or heart problems, can also occur. These risks are extremely rare, though. 

Additionally, labetalol may not be recommended for people who have asthma or certain types of heart problems. If you have one of these conditions, your prescriber may recommend other first-choice medications for hypertension in pregnancy. These medications may include methyldopa or nifedipine (Procardia, Procardia XL). 

Keep in mind: Even though all medications have risks, labetalol is generally well tolerated during pregnancy. And often, the benefit of treating hypertension during pregnancy outweighs the risks. Still, let your provider know if you have bothersome side effects from labetalol so they can adjust dosage or recommend another medication, if needed. And seek medical attention if you experience severe headaches, vision changes, or chest pain at any time

Possible risks for your baby

Like many blood pressure medications, labetalol can cross the placenta and reach your baby. This means your baby may have some level of labetalol in their body while you’re pregnant. But the potential effects of this seem to be minimal. For example:

• Some research suggests that babies born to women taking beta blockers late in pregnancy may have low blood glucose (sugar) and slower breathing just after birth. But the research on this is mixed. 

• There’s also some concern that labetalol use during pregnancy might cause babies to be born smaller than expected. However, the large RCT (high-quality study) discussed earlier found no link between labetalol use during pregnancy and low birth weight. And hypertension in pregnancy itself is a risk factor for low birth weight.

• Additionally, one small study of young children born to women taking labetalol during pregnancy found that the children’s brain development did not appear to be impacted.

Overall, labetalol is considered a safe blood pressure medication to take during pregnancy. And it may be safer than other beta blockers.

Can you breastfeed while taking labetalol?

Research on labetalol during breastfeeding is limited. Labetalol can pass into your breastmilk. But it may do this to a lesser extent than other beta blockers. 

Taking labetalol while breastfeeding is generally considered safe with full-term babies. Still, make sure to weigh the risks versus benefits with your prescriber before taking labetalol while breastfeeding.

Why trust our experts?

Written by:

Daphne Berryhill, RPh

Daphne Berryhill, RPh, has two decades of experience as a clinical pharmacist. She spent most of her career in the Chicago area practicing in-home infusion.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Christina Palmer, MD

Christina Palmer, MD, is a board-certified family physician with a focus on chronic care management, women’s health, and mental health. She’s the co-author of “Open Heart: When Open-Heart Surgery Becomes Your Best Option.”.

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