Research on abortion in mares sheds light on the causes of miscarriages in women

A study conducted at Cornell University offers a new perspective on the causes of early pregnancy loss in both horses and humans. Researchers found that a significant proportion of abortions in mares (42% during the first two months of gestation) were linked to a chromosomal abnormality called triploidy. This research sheds light on the genetic causes of spontaneous abortion, with potential implications for pregnancy in humans. The study analyzed 256 samples of fetuses and placentas from mares that had aborted. The results reveal that triploidy—a condition in which the fetus has three haploid sets of chromosomes—is the primary cause of early abortions. Interestingly, the study shows that chromosomal aberrations are responsible for the majority of abortions occurring before 55 days of gestation. These chromosomal number abnormalities contribute equally to fetal loss in both humans and mares, with triploidy being the dominant type of ploidy during the critical period of organogenesis. Pregnancy in mares provides a unique model for studying human pregnancy due to the similarity between horse and human genomes, as well as similar embryonic development and gestation periods (approximately eleven months in horses versus nine months in humans) and the presence of a single fetus. Unlike other animal models such as rodents, the horse provides valuable data on spontaneous abortions, particularly during the first six weeks of gestation—a period that is currently understudied in human medicine but crucial for embryonic development. Most human miscarriages remain understudied due to a lack of available research material. By exploring the chromosomal abnormalities responsible for early abortions in mares and miscarriages in women, this study establishes the first animal model truly based on quantified and compared data. The goal is to improve gynecological care for both pregnant mares and pregnant women by developing better diagnostic tools and treatments to reduce premature embryonic loss.