The connection between the thyroid gland and milk production has not been well-recognized or appreciated . The good news is that new animal research is providing us insights into the possible effects of thyroid dysfunction. This talk takes a detailed look at hypothyroidism, hyperthyroidism, postpartum thyroiditis and thyroid cancer and the unique challenges each present for lactation, and then discusses treatment strategies and interfacing with the health care team.  Note: This is the most detailed version of this topic.