Overview
The Maternal–fetal Exchange Interface
The placenta is an organ built by two participants.
The placenta is an organ built by two participants. Fetal tissue forms the chorionic plate and branching villi; maternal tissue forms the decidua basalis. Between them lies the intervillous space, where maternal blood circulates around fetal villi. This arrangement lets the fetus obtain oxygen and nutrients and return waste products without normally mixing maternal and fetal blood. The placenta is not simply a filter. It is an exchange surface, an endocrine organ, and a selectively regulated immune boundary. A problem with its development, blood flow, or location can therefore affect fetal growth, maternal health, or both. [1]