Healthy pregnancy hub

Atenolol (Tenormin®)

Last Update: 16 Oct 2025

Welcome to our fact sheet on atenolol during pregnancy and breastfeeding or chestfeeding. This information is based on available published literature. It should not take the place of medical care and advice from your healthcare provider.

The HEALTHY PREGNANCY HUB team is collaborating with MotherToBaby to share information on this topic. The original version is available here (October 2024).

Serene, our chatbot, can also answer your questions about medications during pregnancy.

Please note that this fact sheet is based on United States information and has been adapted for Canada, with a review by our Canadian experts. Minor differences may exist between the two countries. Always consult your healthcare professional for information tailored to your situation.

1. What is atenolol?

Atenolol is a medication that has been used to treat high blood pressure, chest pain (angina), and heart rhythm issues (arrhythmias). It has also been used to treat, prevent, and improve survival after a heart attack. It belongs to the class of medications called beta-blockers. A brand name for atenolol is Tenormin®. 

Sometimes when people find out they are pregnant, they think about changing how they take their medication, or stopping their medication altogether. However, it is important to talk with your healthcare providers before making any changes to how you take this medication. Your healthcare providers can talk with you about the benefits of treating your condition and the risks of untreated illness during pregnancy. 

2. What does research say about the risks during pregnancy?

I take atenolol. Can it make it harder for me to get pregnant?

It is not known if atenolol can make it harder to get pregnant. 

Does taking atenolol increase the chance of miscarriage?

Miscarriage is common and can occur in any pregnancy for many different reasons. Studies have not been done to see if atenolol increases the chance of miscarriage. Studies involving over 2,000 pregnancies on the beta-blocker class did not find an increase in this risk. 

Does taking atenolol increase the chance of birth defects?

Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. Studies have not been done to see if atenolol increases the chance of birth defects. Studies on the use of beta-blockers in general during pregnancy have not reported an increased chance of birth defects. 

Does taking atenolol in pregnancy increase the chance of other pregnancy-related problems?

Atenolol has been linked with reduced growth of the fetus (smaller in size and/or low birth weight), although it is not clear if this happens because of the medication, the condition being treated, or other factors. One study did find that atenolol can directly affect blood flow through the placenta, which might be linked with poor growth of the fetus, causing low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth).  

Some studies have also found that there may be a risk of low blood sugar (hypoglycemia) in the baby at birth. 

Does taking atenolol in pregnancy affect future behavior or learning for the child?

Studies have not been done to see if atenolol can cause behavior or learning issues for the child. 

What screenings or tests are available to see if my pregnancy has birth defects or other issues? 

Prenatal ultrasounds can be used to screen for some birth defects. Ultrasound can also be used to track the growth of the pregnancy. Talk with your healthcare provider about any prenatal screenings or testing that are available to you. There are no tests available during pregnancy that can tell how much effect there could be on future behavior or learning. 

3. Breastfeeding​/ chestfeeding​ while taking atenolol

Atenolol passes into human milk. There have been reports of babies with slow heart rate, low blood pressure, a bluish color in the skin due to a lack of oxygen in the blood (cyanosis), and low body temperature after being exposed to atenolol through human milk. If you suspect the baby has any symptoms (slow heart rate, low blood pressure, a bluish color in the skin, lips, or fingernails) contact the child’s healthcare provider. 

The product label for atenolol recommends people who are breastfeeding or chestfeeding not use this medication. But, the benefit of using atenolol may outweigh possible risks. Your healthcare providers can talk with you about using atenolol and what treatment is best for you. Be sure to talk to your healthcare provider about all your breastfeeding or chestfeeding questions. 

4. What about fathers and sperm donors?

If a male takes atenolol, could it affect fertility or increase the chance of birth defects?

Atenolol may lower the amount of testosterone and cause erectile dysfunction, which could affect a male’s fertility (ability to get a person pregnant). Also, male with conditions like hypertension may have problems with fertility. In general, exposures that fathers or sperm donors have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures here.

Key points

  • Atenolol (Tenormin®) is a beta blocker medication used to treat high blood pressure and other heart problems.
  • It is not yet known whether atenolol increases the risk of miscarriage or birth defects, but the available data on beta blockers in general do not show a higher risk compared to the background risk.
  • Atenolol may slow the baby’s growth during pregnancy, but the reasons are not yet well understood.
  • Atenolol passes into breast milk and can sometimes cause effects in the baby (slow heart rate, low blood pressure, bluish skin, low temperature). It is important to discuss with your healthcare team if you are taking this medication.
  • In males, atenolol may reduce fertility according to some studies, but this usually does not increase risks for the baby.
  • Always talk to your healthcare provider before making any changes to your medication during pregnancy or breastfeeding/ chestfeeding.

References

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Disclaimer

HEALTHY PREGNANCY HUB provides a source of information validated by health professionals; however, this information is provided for informational purposes only and should not replace professional advice. Medical standards and practices evolve as new data becomes available, so it is imperative to consult your doctor or a qualified health professional for any questions or concerns regarding your health without delay or omission. It is the responsibility of your treating physician or any other health professional, based on their independent experience and knowledge of the patient, to determine the best way to evaluate and treat you.

HEALTHY PREGNANCY HUB does not specifically recommend or endorse any test, practitioner, treatment, product, or opinion mentioned on our platform. HEALTHY PREGNANCY HUB also does not replace the individual patient assessment based on the examination by the healthcare provider of each patient and the consideration of laboratory data and other patient-specific factors.

The use of the information available on our site is at your own risk. No person involved in the creation, production, promotion, or marketing of HEALTHY PREGNANCY HUB guarantees or represents, expressly or implicitly, anything regarding the information available on the platform, which is provided “as it is”. All warranties are expressly excluded and disclaimed, including but not limited to implied warranties of merchantability or fitness for a particular purpose, as well as any warranties arising by law or otherwise in law or from trade or usage. Any statements or representations made by any other person or entity are void.

While consulting symptoms or other medical information on our platform may guide your discussions with your healthcare professional, this information should not be used to make a medical diagnosis or determine treatment. Before making changes to your supplement or medication regimen, please discuss with your medical team or contact 811 (Canada) to ensure the relevance of these changes to your individual situation.

Credits
MotherToBaby
Organization of Teratology Information Specialists (OTIS)
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Evelyne Rey
CHU Sainte-Justine
Modupe Tunde-Byass
University of Toronto
R. Douglas Wilson
University of Calgary
Judith Cottin
Enav Zusman
The University of British Columbia
Émy Roberge
Centre hospitalier universitaire Sainte-Justine
Folasade Elizabeth Olaniyan

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