How to Manage Cervical Incompetence by Application of a Cervical Cerclage Suture in the Pregnant Mare

Cervical incompetence in the mare is widely recognized as a major cause of pregnancy failure. Failure to attain adequate closure during pregnancy is a key predisposing factor to ascending placentitis. In humans, cervical insufficiency is of major concern and can result in preterm birth and lateterm abortions, similar to observations in mares. Emerging clinical and laboratory-based evidence suggests that focusing on the uterine cervix may provide significant elements of diagnostic value to identify patients at risk for preterm delivery, offering guidelines to implement preventive intervention. A variety of techniques have been used in human medicine to address cervical incompetence, including medical therapy with progesterone, cervical cerclage, and the placement of a cervical pessary, some of which may be applicable in the mare. A recent study in human medicine compared vaginal progesterone versus cerclage, with the use of placebo/no cerclage as the control treatment. The authors concluded that progesterone and cervical cerclage are equally effective for the prevention of preterm birth and adverse perinatal outcomes in patients with a short cervix and history of preterm birth. A common treatment strategy used on mares that have previously lost a foal because of placentitis or that have anatomical abnormalities in the caudal reproductive tract making them at risk of ascending placentitis is to administer an antimicrobial, a nonsteroidal anti-inflammatory drug and altrenogest daily until delivery of the foal. The shortcoming of this treatment is that mares may still have a preterm delivery/fetal loss with histopathological evidence of ascending placentitis despite treatment. This report describes a technique for cervical cerclage applied to a population of mares with known cervical incompetence.