Foetal blood supply. 1861 illustration showing the circulatory system between a mother's placenta (bottom) and her unborn child (top), through the umbilical cord (red, centre). The placenta is a temporary organ in a pregnant woman that connects the developing foetus via the umbilical cord to the uterine wall to allow nutrient uptake, thermo-regulation, waste elimination, and gas exchange via the mother's blood supply.