Although most women with SCH are asymptomatic, SCH during pregnancy may be associated with adverse outcomes, including miscarriage, preterm birth, pre-eclampsia and gestational diabetes, especially in women who are anti-thyroid peroxidase antibody (TPOAb) positive (van den Boogaard et al., 2011; Negro and Stagnaro-Green, 2014; Alexander et al., 2017; Arbib et al., 2017; Korevaar et al., 2019). Here, TPO is linked to spindle cell hemangioma.