Pathophysiology
Clinical meaning
The umbilical cord is the lifeline connecting the developing fetus to the placenta throughout pregnancy. It contains two umbilical arteries that carry deoxygenated blood and metabolic waste from the fetus to the placenta, and one umbilical vein that carries oxygenated, nutrient-rich blood from the placenta to the fetus. The cord is surrounded and protected by Wharton jelly, a mucoid connective tissue composed primarily of mucopolysaccharides that provides cushioning and prevents compression of the blood vessels. The average cord length is approximately 50 to 60 centimeters, and the average diameter is 1 to 2 centimeters. The cord is covered by a single layer of amnion epithelium continuous with the amniotic membrane. At birth, the umbilical cord is clamped and cut, severing the fetal-placental circulation. The current evidence supports delayed cord clamping (DCC), defined as clamping the cord at least 30 to 60 seconds after birth (and up to 3 minutes in some guidelines), to allow continued blood transfer from the placenta to the newborn. Delayed cord clamping provides the newborn with an additional 80 to 100 mL of blood, increasing iron...