PGR and endometriosis: Previous studies have shown that the aberrant expression of ER, PR, miR-29c, miR-135a, miR-135b, miR-194-3p, miR-196a and miR-92a may contribute to progesterone resistance and impaired decidualisation in endometriosis [22,23,24,25,41,42,43,44,45,46,47,48,49,50,51].