It is important to consider whether the Premarin cream will be used regularly or if it was just a one-time application. The risks of using estrogen during breastfeeding include a decrease in milk production and quality. However, if it was a one-time dose, the likelihood of a significant amount of estrogen passing into breast milk is very low. Estrogen used topically has lower absorption compared to oral consumption. Estrogens are generally considered safe and can even be used for contraception shortly after childbirth. It is usually not necessary to stop breastfeeding after a single dose. If Premarin will be used regularly, it would be best to consult with a doctor to weigh the pros and cons of the treatment. There may be other treatment options available for your symptoms that could be a better choice.