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Is it safe? · Pregnancy Smart

Atenolol During Pregnancy: Why It Is Usually Avoided

Assigned clinical reviewerMatt Stahl· PharmDDraft · pending clinical reviewUpdated

What does the evidence say about atenolol during pregnancy?

  1. In a retrospective cohort of 379,238 singleton pregnancies, atenolol exposure was associated with small-for-gestational-age birth after adjustment, with an odds ratio of 2.4 and a 95% confidence interval of 1.7 to 3.3. Different prescribing indications and residual confounding limit causal interpretation. 1
  2. An American Heart Association scientific statement reports that atenolol has been associated with fetal growth restriction, especially when exposure lasts longer, while noting that recommended blood pressure medicines vary among guidelines. 2
  3. A clinical review lists labetalol and nifedipine among maintenance options in pregnancy and lists atenolol among medicines to avoid because of reduced fetal and placental weight and intrauterine growth concerns. 3
  4. In a Medicaid cohort of beta blocker exposure at delivery, class-wide exposure was associated with newborn hypoglycemia and bradycardia. Atenolol-specific estimates had confidence intervals crossing 1, so the study did not establish a statistically significant atenolol-specific difference. 4
  5. A systematic review found a probable class-wide risk of newborn hypoglycemia and a possible risk of bradycardia after fetal beta blocker exposure, supporting glucose monitoring for 24 hours and consideration of heart-rate monitoring. Drug-specific estimates were imprecise. 5

Is atenolol safe in each trimester?

  • First trimester. Early medication review matters because longer atenolol exposure has been associated with reduced fetal growth. Ask the prescriber whether another blood pressure medicine fits your condition, and do not stop atenolol without a replacement plan.
  • Second trimester. If atenolol remains necessary, blood pressure follow-up and an individualized plan for fetal growth assessment are important. The underlying hypertension can also affect pregnancy outcomes, so medication and disease risks need to be weighed together.
  • Third trimester. Beta blocker exposure near delivery has been associated with newborn low blood sugar and slow heart rate as a class. Tell the birth team about atenolol so they can decide whether newborn glucose and heart-rate observation is appropriate.

Frequently asked questions

Why is atenolol usually avoided during pregnancy?

Atenolol is usually avoided because observational studies and clinical reviews associate it with reduced fetal growth and small-for-gestational-age birth. Those data cannot fully separate the medicine from the hypertension or other reasons it was prescribed, but pregnancy guidance generally favors other options when suitable.

Does atenolol cause a smaller baby?

Atenolol exposure has been associated with smaller size at birth, but an association is not proof that atenolol caused the outcome. Hypertension itself can affect growth, and observational studies cannot remove all differences between people who received atenolol and those who did not.

Is labetalol safer than atenolol during pregnancy?

Pregnancy reviews commonly list labetalol as a preferred blood pressure option and advise avoiding atenolol because of fetal growth concerns. That does not make labetalol risk-free or suitable for everyone. The prescriber should choose based on the blood pressure condition, heart rate, asthma history, and response.

Is atenolol more concerning earlier or later in pregnancy?

The growth concern appears most relevant with longer exposure, so early review can reduce unnecessary duration. Near delivery, beta blockers as a class can also affect newborn glucose or heart rate. There is no verified week at which atenolol changes from acceptable to unacceptable.

What should I do if I became pregnant while taking atenolol?

Contact the prescriber promptly for a medication review, but do not stop atenolol abruptly on your own. The immediate task is to keep the underlying blood pressure or heart condition controlled while the clinician decides whether to switch medicines and whether fetal growth follow-up is warranted.

Can you breastfeed while taking atenolol?

Atenolol can enter milk substantially and accumulate in young infants. LactMed prefers alternatives for a newborn or preterm infant, especially with higher maternal doses. Timing feeds around a dose offers little benefit. Review the medicine and infant monitoring plan with the prescriber and pediatric clinician.

Will a newborn need observation after atenolol exposure?

The birth team may check the newborn's blood sugar and heart rate after late beta blocker exposure. Class-wide evidence supports glucose observation for about 24 hours and consideration of heart-rate monitoring, although atenolol-specific estimates in one large study were imprecise.

Can fetal growth be checked after atenolol exposure?

Yes. A clinician can decide whether serial ultrasound assessment is appropriate based on exposure duration, the reason for atenolol, blood pressure control, and other growth-risk factors. Exposure alone does not predict a specific ultrasound result.

Related in the library

References

  1. Beta‐blocker subtypes and risk of low birth weight in newborns

    PMC · https://pmc.ncbi.nlm.nih.gov/articles/PMC8030941/

  3. Evaluation and Management of Hypertensive Disorders of Pregnancy

    PMC · https://pmc.ncbi.nlm.nih.gov/articles/PMC10617800/

  6. Atenolol - Drugs and Lactation Database (LactMed)

    NCBI Bookshelf · https://www.ncbi.nlm.nih.gov/books/NBK501142/

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.