Because of the low levels of metoprolol in breastmilk, amounts ingested by the infant are small and would not be expected to cause any adverse effects in breastfed infants. Studies on the use of metoprolol during breastfeeding have found no adverse reactions in breastfed infants. Monitor breastfed infants for symptoms of beta blockade such as bradycardia and listlessness due to hypoglycemia.