In animals that give live birth, the<unk>  is the circulatory system of a fetus. The term usually encompasses the entire fetoplacental<unk> , which includes the umbilical cord and the blood vessels within the placenta that carry<unk>  blood. The<unk>  differs from the postnatal<unk> , mainly because the lungs are not in use. Instead, the fetus obtains oxygen and nutrients from the mother through the placenta and the umbilical cord. At birth, the start of breathing and the severance of the umbilical cord prompt various neuroendocrine changes that quickly transforms<unk>  into postnatal<unk> .
Fetal circulation
Cardiac cycle
Fetal movement
Cardiovascular physiology
Hemodynamics
Fetal viability
Coronary circulation
Amniotic fluid index