What is the main function of the uterine arteries in fetal blood supply?

The primary function of the uterine arteries in fetal blood supply is to deliver oxygenated blood to the spiral arteries. The uterine arteries supply blood to the uterus, and from there, the blood enters the spiral arteries within the placenta. These spiral arteries are crucial for providing oxygen and nutrients from maternal circulation to the fetal blood supply through the placenta. This process is vital for fetal development, as it ensures that the fetus receives the necessary oxygen and nutrients needed for growth while also allowing for waste exchange.

The other options do not accurately describe the role of the uterine arteries. The delivery of deoxygenated blood to the placenta is not the primary function of the uterine arteries; instead, this occurs through different pathways. Additionally, the return of waste products from the fetus to maternal circulation does not occur directly through the uterine arteries, and providing nutrients directly to fetal capillaries isn't accurate since nutrients are instead delivered through the placenta.