Umbilical cord morphology and pregnancy outcome.

Traditionally, the prenatal assessment of the umbilical cord (UC) is limited to the assessment of the number of vessels and to the evaluation of umbilical artery blood flow parameters. Morphologic aspects of the UC have usually been studies by pathologists and retrospectively correlated with the perinatal outcome. The introduction of more sophisticated imaging techniques have offered the possibility to investigate the UC characteristics during fetal life from early to late gestation. A number of investigations have demonstrated that an altered structure of the UC can be associated with pathologic conditions (i.e. Preeclampsia, fetal growth restriction, diabetes, fetal demise). Nomograms of the various UC components have been generated and allow the identification of lean or large umbilical cords, entities frequently associated with fetal growth abnormalities and diabetes. A Wharton's jelly reduction has also been invoked as a possible cause of fetal death in the presence of single umbilical artery. Prenatal morphometric UC characteristics as well as arterial and venous blood flow parameters in normal and pathologic conditions will be discussed.