Research overview: zonary placentation in felids

Cats develop a zonary, endotheliochorial placenta that forms a band around the fetus and mediates maternal-fetal exchange during gestation. This overview surveys the structure and development of the feline placenta, its hormone production, and how it supports the growing litter. It compares felid placentation with that of other carnivores and discusses the marginal hematomas characteristic of the cat placenta. The review considers how placental development relates to the timing of pregnancy hormones used in diagnosis and to nutrient transfer that shapes neonate size. Understanding placentation provides context for interpreting pregnancy physiology, prenatal losses, and the relatively altricial state of newborn kittens and cubs across the cat family.