Delayed uterine prolapse in a Thoroughbred mare with retained fetal membranes

A 6 year old Thoroughbred mare was presented to Virginia-Maryland College of Veterinary Medicine’s (VMCVM) Equine Field Service for evaluation of retained fetal membranes (RFM) after aborting twins the night before. Fetal membranes retention was observed by the owners, with no progression for 5 - 6 hours. Initial treatment included gentle manual traction of fetal membranes, administration of oxytocin and flunixin meglumine, and lavage of uterus. Despite expelling large amounts of fluid after lavage, there was no further progress in fetal membranes expulsion. Mare was given another oxytocin injection which caused continued myometrial contractions; however, there was no progress. Due to duration of retention, worsening of clinical signs (increased digital pulses and injected mucus membranes), and lack of improvement, mare was referred to the VMCVM Veterinary Teaching Hospital. She was resedated, and her uterus was lavaged again without dislodging fetal membranes. Mare was placed on IV fluids and broad-spectrum antimicrobials, and was under continued sedation and oxytocin treatment. At 8 hours after presentation, mare’s uterus prolapsed (everted). Mare was given an epidural, uterus was rinsed with hypertonic saline and replaced. A Caslick’s procedure was performed to aid in uterine retention. There was still a small amount of RFM observed after replacement. Hospitalization for treatment included twice-daily uterine lavages, IV fluids, oxytocin, antimicrobials, flunixin meglumine, and omeprazole. Mare was also treated with ice boots, vasodilators, and antiinflammatories to prevent laminitis. Mare was discharged 4 days later with no medications and did not experience any further complications. Uterine prolapse (eversion) is rare in mares, often fatal (from infection), and usually occurs immediately or within a few hours after parturition. Aggressive and prompt treatment of RFM in mares is critical. Regardless, as observed in this case, RFM may be considered a predisposing factor for delayed uterine prolapse.

Keywords: Equine, uterine prolapse, retained fetal membranes

This manuscript was originally published in the journal Clinical Theriogenology Vol 12(3) Sept 2020.  Clinical Theriogenology is the official journal of the Society for Theriogenology (SFT) and the American College of Theriogenologists (ACT).  This content has been reproduced on the IVIS website with the explicit permission of the SFT/ACT.