Transdermal estradiol treatment during breastfeeding: maternal and infant serum concentrations.

We examined estradiol (E2) and estrone (E1) concentrations in breastfeeding mother-infant dyads. The mothers had postpartum depression and were participants in a randomized clinical trial with three treatments (transdermal E2, sertraline, and placebo). Neither infant E1 and E2 concentrations nor infant growth differed across the treatments. Transdermal E2 administration of 50 to 200 mcg/day for breastfeeding women did not affect infant E1 or E2 concentrations or infant growth.