Placental lesions in habitually aborting cats.

An ovariohysterectomy was done on five female cats with a history of habitual abortion in the 3rd to 4th week of pregnancy and the foetuses and placentas examined. Histologic and electron microscopic examination showed multifocal placental necrosis which was deduced to begin in the syncytial trophoblastic cells and to extend to all the cells of the labyrinth. This lesion was followed by foetal autolysis. No bacterial, viral or mycoplasmal agents could be incriminated in the disease.