Moleti M, Di Mauro M, Alibrandi A, et al. - Researchers conducted this retrospective chart review to assess the risk of postpartum thyroiditis (PPT), defined as the occurrence of de novo autoimmune thyroid disease accompanied by thyroid dysfunction in the first year postpartum, in women with Hashimoto’s thyroiditis (HT) antedating pregnancy. The sample consisted of pregnant women with HT antedating pregnancy seen in a University Hospital (2008-2017), who were followed from preconception up to one year after delivery. According to their thyroid status at the time of diagnosis, 167 women preconceptionally diagnosed with HT, and classified as hypothyroid-HT (Hypo-HT, n = 98) or euthyroid-HT (Eu-HT, n = 69). Data reported that PPT occurred in 65/167 women, with a Eu-HT rate statistically higher than in the Hypo-HT group. Findings suggested that PPT may occur in hypothyroid HT women on LT4 therapy, but significantly less often than in euthyroid HT women. The four-fold higher risk of PPT in HT women sustaining euthyroidism at 1st -trimester of gestation indicates that the risk of PPT could be linked to the amount of unaffected thyroid tissue.