Canis ISSN: 2398-2942

Abortion / stillbirth

Contributor(s): Kyle Braund, Carlos Pinto

Introduction

  • Common problems but relatively little is known about infectious and non-infectious abortifacients in dogs.
  • Cause:
    • Fetal resorption: unknown.
    • Abortion: toxoplasmosis, canine herpesvirus infection, canine parvovirus (based on behavior of porcine parvovirus as an abortifacient), canine brucellosis (relatively common in Central and South America, and Southern USA; serological evidence of its presence in the UK; sporadic cases reported in the European Union).
    • Stillbirth: fetal anomalies, dystocia/prolonged labor.
    • Fetal death with retention in the uterus or abdominal cavity: intra-uterine or intra-abdominal presence of fetus(es) beyond the normal time of gestation owing to fetal death and uterine atony, fetal mummification or uterine rupture.
  • Signs: premature milk production, vomiting, vaginal discharge, signs of abdominal pain.
  • Diagnosis: specific cause often unidentified in the vast majority of cases.
  • Treatment: antibiotics.
  • Prognosis: most bitches become immune to infectious cause (except canine brucellosis and probably herpesvirus infection) and subsequently reproduce normally.

Pathogenesis

Etiology

  • Relatively little is known.
  • Chemical or environment abortifacient exposure.
Infection Fetal anomalies
  • Schistosoma reflexus.
  • Meningeocoele.
  • Amelia.
Dystocia
  • Dystocia Dystocia.
  • Maternal causes (primary or secondary uterine inertia; obstruction of birth canal).
  • Fetal causes (oversized fetuses; abnormal presentations).
Fetal resorptionLow progesterone deficiency secondary to luteal insufficiency (hypoluteoidism)
  • Recurrent pregnancy loss may be associated with low concentrations of serum progesterone Progesterone assay.

Predisposing factors

General
  • Inherited predisposition (chromosomal abnormalities of dam/fetus?).
  • Nutritional imbalance (inadequate carbohydrate intake may lead to ketosis → pregnancy toxemia).
  • Age-related changes.
  • Fatty infiltration of myometrium.
  • Deficiency in neuroendocrine regulation.
  • Systemic disease in bitch.

Pathophysiology

  • Bacterial toxins affect placenta with release of prostaglandin F2-alpha causing luteolysis and myometrial contractions.
  • Insufficient uterine activity or failure to respond to fetal signals → primary uterine inertia (most common cause of dystocia in dogs).
  • Dystocia Dystocia → hypoxia → anus relaxes → meconium escapes into the amniotic fluid → inhaled by fetus.

Timecourse

  • Depends on cause.

Epidemiology

  • Depends on cause, eg brucellosis and canine herpesvirus infection are transmitted venereally and via the products of abortion.

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.
  • Lamm C G & Makloski C L (2012) Current advances in gestation and parturition in cats and dogs. Vet Clin North Am Small Anim Pract 42 (3), 445-456 PubMed.
  • Verstegen J, Dhaliwal G, Vestegen-Onclin K (2008) Canine and feline pregnancy loss due to viral and non-infectious causes: a review. Theriogenology 70 (3), 304-319 PubMed.

Other sources of information

  • Johnston S D, Root-Kustritz M V, Olson P N S (2001)Canine and Feline Theriogenology.Philadelphia, W B Saunders Co.


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