Background: Uterine cyst is an important reproductive disorder in the equine industry as it can render mares subfertile or infertile. Although age, parity and endometrosis are considered as primary contributors of uterine cysts, the pathogenesis of uterine condition is not completely understood. There are studies indicating the association between size of ovarian reserve and uterine function and disorders; however, limited information is available on the relationship between ovarian reserve and uterine cyst in mares.
Objectives: Therefore, the present study was conducted to evaluate the relationship between anti-Müllerian hormone (AMH) concentration, as a reliable indirect marker of ovarian reserve, and uterine cyst in mares.
Methods: To this end, AMH concentration was evaluated in 38 mares, including young mares without uterine cyst (Young category; mares aged < 10 years old; n = 27), old mares without uterine cyst (Old category; mares aged ≥ 10 years old; n = 6) and mares with uterine cyst (Cystic category; mares aged ≥ 10 years old; n = 5). In this regard, analysis of AMH concentration among various categories of mares was initially analyzed using an unadjusted univariable model, and then, it was analyzed using a multivariable model adjusted for age of mares.
Results: The unadjusted analysis showed lower AMH concentration in cystic mares (0.38 ± 0.12 ng/ml) than that in young (1.08 ± 0.06 ng/ml) and old (0.95 ± 0.16 ng/ml) mares (P ≤ 0.05). Yet adjusted analysis for age revealed a tendency for lower AMH concentration in cystic than old mares (P = 0.074). Indeed, the adjusted model implicated that the difference between young and cystic mares, which was observed in the unadjusted analysis, was more associated with age difference between these categories of mares. However, the difference between old and cystic mares, which was observed in the unadjusted analysis, was more associated with uterine cyst.
Conclusion: In conclusion, this study showed lower AMH concentration in mares with uterine cyst as compared with their age-matched counterparts, which could be an implication for a potential role of ovaries and ovarian reserve in the pathogenesis of uterine cyst.