Chronic Endometrial Degeneration (CED): an international expert recommendation to replace the term 'endometrosis' in mares.

The term 'endometrosis', coined in 1992 to describe chronic degenerative changes of the equine endometrium, is descriptively imprecise and readily confused with 'endometritis' and the human gynaecological condition 'endometriosis'. A modified four-round electronic Delphi (e-Delphi) process was conducted with an international panel of eight specialists to achieve consensus on a replacement term. Fifteen candidate terms were evaluated in Round 1 using a 7-point Likert scale and preference rankings; terms were retained if >50% of respondents scored ≥4/7. Round 2 (Refinement) evaluated shortlisted terms plus five panel-proposed new terms against a ≥75% threshold. Round 3 (Consensus Vote) presented six retained terms and four variants for a forced-choice ranking. The primary criterion (≥75% scoring ≥6/7) was not met by any individual term, therefore a pre-specified Round 4 binary vote resolved the outcome. 'Endometrosis' (proposed for retention by one panel member) was near-unanimously rejected in Round 2 (median 1/7; IQR 1-3). In Round 3, Chronic Endometrial Degeneration (CED) achieved the highest support (median 6/7; IQR 5-7; 71.4% scoring ≥6/7) and all seven respondents placed CED or its variant Chronic Equine Endometrial Degeneration (CEED) as their first preference. In Round 4, five of eight panel members (62.5%) selected CED. Chronic Endometrial Degeneration (CED) is recommended as the replacement term for 'endometrosis' in equine endometrial biopsy reporting, clinical practice and scientific publication. CED is well-suited as a consensus term; it is concise, broad and generates a memorable acronym. CEED is an accepted alternative where species specificity is required.