Chromosomal errors are a common cause of pregnancy loss in mares, researchers from the Royal Veterinary College (RVG), as part of a team from Cornell University, have discovered in a new study.
In humans, chromosomal errors are a common cause of miscarriage, accounting for up to 82% of pregnancy loss. Due to the similarities between human and horse chromosomal structures and other pregnancy characteristics, this research supports the use of horses as a novel model organism to study miscarriage in women. The findings of this study mean it is possible to now account for potential causes in 60-70% of equine early pregnancy loss–previously this figure was only around 20-30%.
The study investigated the prevalence of aberrations in chromosomes in 256 cases of pregnancy loss–collected from 244 mares between 2013 and 2023–finding that triploidy (three haploid sets of chromosomes), was the most common aberration (42%). Other abnormalities identified included trisomy–the presence of one extra whole chromosome–and monosomy–the loss of one whole chromosome, in almost 12% of pregnancies.
The team behind the study was overseen by Dr Amanda de Mestre, from Cornell's Baker Institute for Animal Health and included the RVC's Dr Jessica Lawson as well as other researchers from Texas A&M University and University of California Davis. Other lead authors included Dr Shebl Salem, a postdoctoral fellow at Cornell and Mr Don Miller, laboratory manager of the Cornell Equine Pregnancy Laboratory.
For the full paper, please click here.
Dr. Jessica Lawson, Research Fellow at the Royal Veterinary College, said, “In addition to the significant findings in the early stages of the equine pregnancy we, for the first time, have identified sub-chromosomal aberrations in an aborted fetus and a stillborn foal. These aberrations likely constitute a rare but important cause of later term pregnancy loss, and we look forward to continuing to investigate the clinical significance of these genomic changes.”
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