Equis ISSN 2398-2977

Uterus: uterine artery/vein rupture

Contributor(s): Terry Blanchard, William Ley, Graham Munroe, Elaine Watson, Madeleine L H Campbell

Introduction

  • Occurs in the brood mare in late pregnancy or as a complication of parturition.
  • Cause: rupture of uterine artery usually in late pregnancy or at parturition as a result of degenerative changes in artery. Can be associated with uterine torsion/rupture, trauma during violent foaling (particularly assisted).
  • Signs: abdominal pain where rupture bleeds into broad ligament (no overt bleeding); bleeding into the abdomen presents as a blanching of the mucous membranes, shock and sudden collapse or death.
  • Diagnosis: clinical signs and confirmed by rectal examination - not always possible to demonstrate hematoma in broad ligament - depends upon location; also abdominocentesis for evidence of abdominal bleeding.
  • Treatment: keep mare quiet (?mild sedation), treat shock and restore blood volume. Pain relief.
  • Prognosis: poor, hemorrhage may be fatal.

Pathogenesis

Etiology

  • Rupture of the uterine artery (rarely utero-ovarian or external iliac) in late pregnancy, during parturition or immediately post-partum (up to several days).
  • Right-sided vessels more commonly affected. ? Due to displacement of uterus to left by cecum.

Predisposing factors

General

  • Repeated increase/decrease in size of vessels during pregnancy and parturition create weakened areas in arterial wall.
  • Increasing weight and pull on weakened arteries due to distended uterus in late pregnancy.
  • Further strain by parturition, assisted deliveries or stress post-partum.
  • Low systemic copper levels.

Pathophysiology

  • Rupture of uterine artery (occasionally utero-ovarian or external iliac) in late gestation/parturition or immediately post-parturient (up to 24 h).
  • Subsequent clinical signs and prognosis are related to whether bleeding is contained within the broad ligament or occurs directly into the peritoneal cavity or ovarian tissue.
  • If tear is small and remains within the broad ligament the blood may form a large hematoma, leading to back pressure and control of the hemorrhage.
  • The hematoma may rupture later permitting further hemorrhage.
  • Larger tears or bleeding not confined to the broad ligament lose increased amounts of blood into the peritoneal cavity and death is common.

Timecourse

  • Minutes to days.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Crabtree J (2012) Peripartum problems in mares 2. Postpartum problems. In Pract 34 (8), 462-471 VetMedResource.
  • Dolente B A (2004) Critical peripartum disease in the mare. Vet Clin North Am Equine Pract 20 (1), 151-165 PubMed.
  • Frazer G S (2003) Postpartum Complications in the Mare: Part 1. Conditions Affecting the Uterus. Equine Vet Educ 15 (1), 36-44 VetMedResource.
  • Rossdale P D (1994) Differential diagnosis of postpartum haemorrhage in the mare. Equine Vet Educ 6, 135-136 Wiley Online Library.
  • Wenzel J G W, Caudle A B & White N A (1985) Treating for uterine intramural hematoma in a horse. Vet Med 80 (3), 66-69 VetMedResource.
  • Pascoe R R (1979) Rupture of the utero-ovarian or muiddle uterine artery in the mare at or near parturition. Vet Rec 104 (4), 77 PubMed.

Other sources of information

  • England G C W (1996) Allen's Fertility and Obstetrics in the Horse. 2nd edn. Blackwell Science Ltd.
  • Zent W W (1987) Postpartum Complications. In: Current Therapy in Equine Medicine. Vol 2. Ed: Robinson N E. pp 544.
  • Arthur G H, Noakes D E & Pearson H (1983) Veterinary Reproduction and Obstetrics. 4th edn. Bailliere Tindall.
  • Rossdale P D & Ricketts S W (1980) Equine Stud Farm Medicine. 2nd edn. Bailliere Tindall.


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