The water content of the human umbilical cord

105 umbilical cords from 53 term and 52 preterm newborn infants were freeze-dried after removal of the blood vessels, to determine the water content. The mean umbilical cord water content (i.e. mean of water content of fetal and placental ends of the cord), was 88.9% (SD 2.73) for term cords and 91.9% (SD 1.99) for preterm cords. The mean water content fell with increasing gestation. The fetal end of the cord had a significantly higher water content than the placental end. Similarly, the volume of a 4-cm length segment of cord was significantly greater at the fetal than placental end. There was no correlation between cord water content or volume and several other variables including birthweight, size for gestational age and placental weight. These observations suggest a metabolically active role for the umbilical cord.