An interesting case of early pregnancy loss in a mare with persistent endometrial cups

摘要

A recent extensive survey of efficiency on Thoroughbred studfarms throughout England revealed overall pregnancy loss rates of around 8% between Days 15 and 40 after ovulation, 4% between Day 40 and the traditional 1 st October pregnancy check around Day 150, and a further 2% between October and term (Allen et al. 2007). Possible noninfective causes of the preimplantation Days 15-40 losses include accidental misalignment of chromosomes at the time of fertilisation, failure of maternal recognition of pregnancy, perhaps due to obstruction of embryonic mobility by the presence of endometrial cysts (Bracher et al. 1992), persisting bacterial or fungal endometritis (Asbury and Lyle 1993), or inadequate production of histotroph for nidation of the embryo due to age-related degenerative changes in the endometrial glands (Kenney and Doig 1986). Possible causes of mid-gestation losses between Days 40 and 150 might include lethal karyotypic abnormalities inhibiting embryogenesis and fetal development, a failure of fetomaternal interdigitation and placental development (Allen 1982), or inadequate primary and/or secondary luteal development and function (Squires and Ginther 1975). Excessive torsion of the umbilical cord causing a vascular crisis (Whitwell 1975), or ascending bacterial or fungal placentitis (LeBlanc et al. 2002), are common causes of late stage abortion.