Evaluation of fetal membranes in mares postpartum: literature review

The placenta is the organ responsible for the interaction between mom and fetus throughout pregnancy. After birth, the placenta stop doing its function and, as it is subdivided into different membranes, now called fetal membranes. The objective of this review is to describe the anatomo-physiology of this organ and discuss the importance and correct way of examining fetal membranes in postpartum mares, taking into account the normal and abnormal findings that can be identified. The placenta acts as a barrier against pathogens and immune components and participates in the synthesis and transport of hormones essential for maintaining pregnancy. The evaluation of fetal membranes provides us with information regarding the health of the newborn foal, as well as the integrity of the reproductive tract of foaling mares and the possible damage that may occur postpartum. Ideally, fetal membranes should be evaluated as soon as they are completely externalized and the weight should be approximately 11% of the newborn foal’s live weight. Changes in color and increase in weight may indicate inflammation or even serious infections, making it thicker and opaque, and the blood vessels more evident and congested. Knowledge of the anatomy and functions of the placenta, together with an adequate assessment of the fetal membranes, has a crucial role in the clinical examination of the dam and foal, as well as allowing for early interventions and the necessary support for sick foals.