A study of horses – which share many important similarities with humans in their chromosomes and pregnancies – revealed that 42% of miscarriages and spontaneous abortions in the first two months of pregnancy were due to complications from an extra set of chromosomes, a condition called triploidy. Over that embryonic period [up to eight weeks from conception], triploidy had rarely been reported in mammals outside of women. The study tells us that over the first six weeks of gestation, this will likely be the primary cause of pregnancy loss following natural conception.
" Mandi de Mestre, professor of equine medicine at Cornell University de Mestre is the corresponding author of "Naturally Occurring Horse Model of Miscarriage Reveals Temporal Relationship Between Chromosomal Aberration Type and Point of Lethality," under embargo until 3pm ET on August 5, 2024 in the Proceedings of the National Academy of Sciences. Human miscarriages occur in 10-20% of pregnancies and are commonly associated with chromosomal errors, but there have been no suitable animal models that truly duplicate the features of the condition. The new research findings will help veterinarians better understand the causes of pregnancy loss in horses and identifies horses as an excellent model for studying human miscarriage.
"We were able to study the impact of chromosome errors across the entire pregnancy in the horse," de Mestre said. "We found that triploidy is only associated with losses in early pregnanc.