Peer-reviewed veterinary case report
Ozone treatment helped 10 out of 11 subfertile mares get pregnant
By Moroni, R et al.·Published in Journal of equine veterinary science·2026·Department of Veterinary Sciences, Italy·View original on PubMed →
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Original publication title: Effects of intrauterine ozone insufflation in eleven subfertile mares: a case series.
- Species:
- horse
Plain-English summary
This study looked at a new treatment using ozone gas for eleven mares that had trouble getting pregnant for at least a year, despite multiple attempts at insemination. The mares underwent a procedure to clean out their uterus and take a tissue sample, followed by three days of ozone treatment inside the uterus. After this, the mares were inseminated again, and pregnancy was confirmed two weeks later. Out of the eleven mares, ten became pregnant, and nine of them successfully gave birth to healthy foals. The treatment seemed to help improve the mares' reproductive health, but more research is needed to fully understand its effects.
Abstract
Equine persistent breeding-induced endometritis can lead to chronic uterine inflammation and fibrosis, reducing fertility. Intrauterine ozone (O₃) has recently been proposed as a potential treatment for mares unresponsive to conventional therapies. This case series describes O₃ treatment in eleven mares barren for at least one year despite multiple inseminations attempts. During the first oestrous cycle, low-volume uterine lavage and endometrial biopsy were performed, followed by 3 consecutive days of intrauterine O₂-O₃ gas insufflation. In the subsequent cycle, both procedures were repeated and mares were inseminated with fresh/fresh-cooled semen. Pregnancy was confirmed 14 days post-ovulation and was monitored until parturition. Ten/11 (90.9%) mares conceived and 9/11 (81.8%) delivered a live foal. Post-treatment biopsies showed a significant increase in CD163+ M2 macrophages, suggesting a positive influence of O₃ on endometrial tissue remodeling. These results suggest that O₃ therapy may contribute to fertility restoration in subfertile mares, but further studies are needed.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/41513112/