Rupture of the uterus occurs at the time of foaling. It can be caused by the foal, putting its foot through the wall of the uterus, or it can be caused by a person putting a finger through the wall of the uterus whilst trying to help deliver the foal. Most cases of uterine rupture occur during difficult foalings.
Tears may not be obvious at the time of foaling, but become apparent soon afterwards when the mare starts to show clinical signs of peritonitis (infection and/or inflammation of the lining of the abdominal cavity) and/or colic. These include depression, fever, anorexia and all the signs associated with colic (pawing at the ground, rolling, etc). A thorough examination of the mare, including a rectal examination, palpation of the uterus via the vagina, and a peritoneal tap to obtain a sample of fluid from the peritoneal cavity (abdomen), will reveal the uterine tear. Occasionally the tear is very large and abdominal viscera (organs) prolapse through the tear into the uterus and out of the vulva to appear externally. This can occur during foaling or very shortly afterwards. Treatment will depend on the size of the tear and the owner’s decision. Small tears may respond to medical therapy, such as antibiotics, anti-inflammatories, and lavage of the peritoneal cavity with sterile fluids. Larger tears should be repaired surgically, which requires referral to a hospital. If the abdominal viscera have prolapsed and become contaminated, the prognosis is very poor. For less severe cases, the prognosis for survival is variable, but can be poor for breeding soundness. Adhesions can form between the uterus and other organs in the abdomen, making it difficult for the mare to conceive or remain in foal. Also, adhesions can lead to colic.
