The placenta and its functions: maturity and the at-risk fetus

Abstract

The placenta, the structure through which maternal-fetal exchanges take place, has several other important functions. The well-being of the fetus depends upon it receiving an adequate supply of oxygen and nutrients, and to achieve this it is essential that the flow and composition of the maternal blood reaching the placenta is normal, that the amount of healthy functioning placental tissue is adequate, and that the fetus itself is normal and able to utilize properly the supplies received and to eliminate waste products. Maternal-fetal exchanges occur through the chorionic villi where the bloodstreams of the mother and baby are separated by the fetal capillary endothelium, connective tissue of the mesoderm and trophoblast (see page 31). Exchanges take place either by diffusion or more active processes in which cells ingest surrounding fluid (pinocytosis). Experts in the field of placental function and research consider that the term ‘placental insufficiency’ as the cause of fetal deprivation should be avoided, as faults in the maternal supply line to the placenta are usually factors of more significance (Gruenwald, 1975)*.