This sheet talks about exposure to atenolol in a pregnancy and while breastfeeding. This information should not take the place of medical care and advice from your healthcare provider.

What is atenolol?

Atenolol is a drug known as a beta-blocker. A brand name for this drug is Tenormin®. Atenolol is also available in combination with the diuretic drug chlorthalidone (Tenoretic®). Atenolol is used to treat high blood pressure, chest pain (angina), and rhythm issues with the heart (arrythmias). It is also used to treat, prevent, and improve survival after a heart attack. MotherToBaby has a general fact sheet on beta-blockers, which can be found at: https://mothertobaby.org/fact-sheets/beta-blockers/pdf/.

I take atenolol. Should I stop taking it before I get pregnant?

You should not stop taking this medication abruptly. Talk with your healthcare provider about this medication if you are planning a pregnancy or have found out that you are pregnant. It will be important to discuss the best way to treat your medical condition during pregnancy.

Does taking atenolol increase the chance for a miscarriage?

Miscarriage can occur in any pregnancy. Studies have not been done on pregnant women to see if atenolol might increase the chance for miscarriage if used in early pregnancy.

Does taking atenolol in the first trimester increase the chance of birth defects?

In every pregnancy, a woman starts out with a 3-5% chance of having a baby with a birth defect. This is called her background risk. There is not enough information available to know if first trimester use of atenolol could increase the chance of having a baby with a birth defect. Atenolol did not cause birth defects when given to animals early in pregnancy. The small number of available studies on beta-blockers used in pregnancy, in general, did not find a higher chance for birth defects.

Can taking atenolol cause other pregnancy complications?

Atenolol has been associated with reduced growth of the baby (smaller in size and/or low birth weight). It is not clear if this happens because of the atenolol, the health condition that the atenolol is used for, or both. One study did find that atenolol can directly affect blood flow through the placenta, which might be associated with poor growth of the baby.

Can taking atenolol near delivery cause problems for the baby?

Atenolol use in late pregnancy may cause the newborn baby to have a slowed heart rate and low blood sugar. In the case reports noting these symptoms, the newborns got better in a couple days without treatment. It is not known how often this would happen, but it is not expected to occur in all babies.

Can I breastfeed while taking atenolol?

Maybe. Talk with your healthcare provider about this medication if you plan to breastfeed. Atenolol can get into breast milk in amounts that can affect the baby. There is a case report of a baby that experienced a slow heart rate, low blood pressure, and low body temperature after being exposed to this medication via breast milk.

Babies that are born prematurely (before 37 weeks) or those that have kidney disease might be more sensitive to this medication in breastmilk. If you are worried about any symptoms the baby has contact the child’s healthcare provider. Talk to your healthcare provider about all of your breastfeeding questions.

What if the father of the baby takes atenolol?

In general, exposures that fathers have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet on Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/pdf/.

Selected References:

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  • Easterling TR, et al. 1999. Prevention of preeclampsia: a randomized trial of atenolol in hyperdynamic patients before onset of hypertension. Obstet Gynecol; 93(5 Pt 1):725-733.
  • Eyal S, et al. 2010. Atenolol pharmacokinetics and excretion in breast milk during the first 6 to 8 months postpartum. J Clin Pharmacol; 50:1301-9.
  • Lip GY, et al. 1997. Effect of atenolol on birth weight. Am J Cardiol; 79: 1436-8.
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  • Schimmel MS, et al. 1989. Toxic effect of atenolol consumed during breast feeding. J Pediatrics; 114:476-8.
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