ESR1 and adenomyosis: The consistent increase in ER protein expression in adenomyosis lesions (Zhang et al., 1999; Zeng et al., 2017), particularly during the SP (Konopka et al., 1998; Ueki et al., 2004; Mehasseb et al., 2011), provides evidence for hyper-oestrogenism to play a role in the pathogenesis of adenomyosis.