Postpartum Hemorrhage in Mares

Bleeding into the broad ligament of the uterus or directly into the abdominal cavity (hemoperitoneum or hemoabdomen) is a common and often fatal postpartum emergency in broodmare practice.

Occasionally, mares may bleed before foaling or into their uterus. Mares that are older and have had several foals are at an increased risk. Rupture of arteries around the time of foaling has been associated with copper deficiency because copper is important for collagen (an important connective tissue) production. However, this association is fairly weak and has not been proven.

Most of the time, bleeding occurs on the right side because the cecum is on the right, and it is believed that the cecum displaces and potentially stretches the right uterine artery during pregnancy. Clinical signs of hemoabdomen include sudden death, colic (often severe), and signs of anemia (pale gums, lethargy, etc.).

The most important part of treatment is to keep mares as calm as possible by minimizing stress. Acepromazine lowers blood pressure and provides sedation, but the dose should be adjusted according to the degree of blood loss to prevent excessive hypotension. Many affected mares are extremely painful and require significant pain relief with morphine, butorphanol, and nonsteroidal anti-inflammatory drugs. Aminocaproic acid is usually administered with a low rate of intravenous fluids to stabilize and prevent breakdown of blood clots. Some mares may require blood transfusions, which provide additional red blood cells as well as clotting factors.