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Equine veterinary journal2020; 53(5); 996-1003; doi: 10.1111/evj.13386

Incidence and causes of pregnancy loss after Day 70 of gestation in Thoroughbreds.

Abstract: Pregnancy loss after Day 70 of gestation manifests as abortion, stillbirth or perinatal death. While previous studies have reported the diagnoses of laboratory submissions, none have quantified the incidence and causes of abortions, stillbirths and perinatal mortality at a population level. Objective: To report the incidence and causes of pregnancy loss after Day 70 of gestation in a cohort of Thoroughbreds. Methods: Retrospective cohort study. Methods: Outcomes of Day 70 pregnancies were collected from eight Thoroughbred farms over the 2013-2017 breeding seasons. Stud, veterinary and laboratory records were supplemented with publicly available data. Cause of loss was categorised using custom criteria. Results: Data were collected on 3,586 pregnancies from 1,802 mares. The incidence risk of a pregnancy failing to produce a live foal at 24 hours post parturition was 7.3% (95% confidence interval (CI) 6.5-8.2, equating to 7.3 cases per 100 Day-70 pregnancies). The incidence of pregnancy loss between Day 70 and 300 of gestation, Day 301-315 and stillbirth/perinatal death was 4.0% (95% CI 3.4-4.7), 0.3% (95% CI 0.2-0.6) and 1.4% (95% CI 1.1-1.9) respectively. Of the pregnancy losses where tissue was available, 61.1% were submitted for post-mortem examination. The incidence risk of loss due to umbilical cord-related pathologies was 1.5% (95% CI 1.1-1.9), 0.4% (95% CI 0.2-0.6) for noninfectious placental disease and 0.3% (95% CI 0.2-0.6) for both infectious placentitis and Equine Herpesvirus infection. No primary diagnosis was made in 11.2% of the cases which underwent full post-mortem examination. Conclusions: It was not possible to differentiate between intra-partum stillbirth and early post-partum death. Conclusions: Pregnancy loss after Day 70 of gestation is a significant source of loss in the Thoroughbred with umbilical cord-related pathologies being the most commonly diagnosed cause. Reporting the incidence of pregnancy loss at a population level with clear case definitions will allow for accurate global comparisons.
© 2020 EVJ Ltd.
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Publication Date: 2020-12-14 PubMed ID: 33205445DOI: 10.1111/evj.13386Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research paper examines the frequency and causes of pregnancy loss after the 70th day of gestation in Thoroughbred horses, categorizing pregnancy loss as either abortion, stillbirth or early neonatal death. Data was gathered from eight Thoroughbred farms over a period of five years (2013-2017) and key results indicate that 7.3% of mares failed to produce a live foal after 24 hours of parturition.

Methodology

  • The researchers carried out a retrospective cohort study on Thoroughbreds.
  • They collected the outcomes of 70-day pregnancies from eight Thoroughbred farms over the course of five breeding seasons from 2013 to 2017.
  • The researchers used stud, veterinary and laboratory records and supplemented this with publicly available data.
  • The cause of pregnancy loss was categorized using custom criteria.

Results

  • Information from 3,586 pregnancies from 1,802 mares was collected.
  • They found that the risk of a pregnancy not resulting in a live foal at 24 hours post parturition was 7.3%.
  • The risk of pregnancy loss between Day 70 and 300 of gestation was 4.0%, and dropped to 0.3% during Day 301-315, with 1.4% risk of stillbirth or neonatal death.
  • Of the pregnancy losses where tissue was available, 61.1% were submitted for post-mortem to determine the cause of death.
  • Umbilical cord-related pathologies were the most common cause, resulting in 1.5% of the losses, while non-infectious placental disease and Equine Herpesvirus infection each caused 0.3% of the losses.
  • No primary diagnosis could be made in 11.2% of the cases that underwent full post-mortem examination.

Conclusions

  • The researchers determined that it was impossible to distinguish between intra-partum stillbirth and early post-partum death.
  • They concluded that pregnancy loss after Day 70 of gestation is a considerable source of loss in the Thoroughbred population.
  • The most common cause of these losses was umbilical cord-related pathologies.
  • The researchers believe that reporting the frequency of pregnancy loss at the population level with clear case definitions will allow for accurate global comparisons.

Cite This Article

APA
Roach JM, Foote AK, Smith KC, Verheyen KL, de Mestre AM. (2020). Incidence and causes of pregnancy loss after Day 70 of gestation in Thoroughbreds. Equine Vet J, 53(5), 996-1003. https://doi.org/10.1111/evj.13386

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 53
Issue: 5
Pages: 996-1003

Researcher Affiliations

Roach, Jessica M
  • Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, UK.
Foote, Alastair K
  • Rossdales Laboratories, Newmarket, UK.
Smith, Ken C
  • Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK.
Verheyen, Kristien L
  • Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK.
de Mestre, Amanda M
  • Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, UK.

MeSH Terms

  • Abortion, Veterinary / epidemiology
  • Abortion, Veterinary / etiology
  • Animals
  • Female
  • Horse Diseases / epidemiology
  • Horse Diseases / etiology
  • Horses
  • Incidence
  • Parturition
  • Placenta
  • Pregnancy
  • Retrospective Studies

Grant Funding

  • Alborada Trust

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Citations

This article has been cited 9 times.
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