Atenolol in pregnancy and breastfeeding

Atenolol is contraindicated in pregnancy.

Where does this data come from? In 1 small study, atenolol started at 12 to 24 weeks’ gestation resulted in clinically significant fetal growth restriction and decreased placental weight compared with placebo. (1) A retrospective review confirms that atenolol use may be detrimental in early pregnancy. (2) However, findings are reassuring in late pregnancy as a 1-year postpartum follow-up study showed normal development of infants exposed to atenolol in the last trimester of pregnancy. (3)

Mechanism: Atenolol may decrease uteroplacental blood flow; may impair fetal response to hypoxic stress; risk of growth restriction when started in first or second trimester; and may be associated with neonatal hypoglycemia at higher doses.

In conclusion: Atenolol use should probably be avoided in pregnancy because it has been associated with slightly lower birth weights.

Breast-feeding: Atenolol is concentrated in breast milk, possibly to levels that could affect the infant. (4) Atenolol should not be used in nursing mothers.

-IkaN (Nakeya Dewaswala Bhopalwala)

References:

1. Butters L, Kennedy S, Rubin PC. Atenolol in essential hypertension during pregnancy. 1990;301(6752):587-9.

2. Lip GYH, Beevers M, Churchill D, Shaffer LM, Beevers DG. Effect of atenolol on birth weight. The American Journal of Cardiology. 1997;79(10):1436-8.

3. Reynolds B, Butters L, Evans J, Adams T, Rubin PC. First year of life after the use of atenolol in pregnancy associated hypertension. 1984;59(11):1061-3.

4. Atkinson H, Begg EJ. Concentrations of beta-blocking drugs in human milk. The Journal of Pediatrics. 1990;116(1):156.