Maternal hypothyroidism may be prior to pregnancy and childbirth or secondary to postpartum thyroiditis with an incidence of 3 to 16% and most of the time is temporary, limited to about 6 months (Serrano 2014, Muller 2001).Thyroiditis can occur in two phases, hyperthyroidism followed by hypothyroidism, but almost half of the time the symptoms are exclusively hypothyroidism (Stagnaro 2012).There is no data to recommend universal screening, but it does exist in women with type 1 diabetes mellitus or associated depression (Abalovich 2007). Due to its sharing common symptoms, hypothyroidism can be confused with postpartum depression (Serrano 2014) but no significant link has been proven between them (Stagnaro 2012, Lucas 2001).Although there is not much evidence, it is believed that maternal hypothyroidism can cause hypogalactia (Serrano 2014). However, cases of galactorrhea without hyperprolactinemia have been reported in women affected with hypothyroidism (Oana 2015, Takai 1987). The treatment of hypothyroidism with hormone replacement is compatible with breastfeeding (Alexander 2017, Serrano 2014). The concentration of liothyronine (T3) in breast milk is much higher than that of levothyroxine (T4), which is usually very low or undetectable (Jansson 1983, Sato 1979). Therefore, and because of greater experience, levothyroxine is more recommended than liothyronine for the treatment of hypothyroidism in general and during breastfeeding (Alexander 2017, Serrano 2014, Carney 2014, Yazbeck 2012, Stagnaro 2011, Okosieme 2008, Nava 2004). During pregnancy, the need for treatment with replacement hormone usually increases, decreasing sharply after delivery, so it is necessary to return to the usual dose taken prior to pregnancy (Serrano 2014). See below the information of these related products: