SONOGRAPHY OF THE UMBILICAL-CORD

Knowledge of the development, normal sonographic appearance, and poten tial abnormalities of the umbilical cord is important in fetal assessm ent, The umbilical cord can be visualized throughout most of gestation and is detectable sonographically soon after visualization of the fet al pole, The normal umbilical cord is 50-60 cm long and may coil as ma ny as 40 times, usually to the left, Abnormalities in umbilical cord s ize, degree of coiling, attachment, and position can have important im plications for the outcome of the pregnancy, Structural abnormalities of the umbilical cord such as single umbilical artery, knots, cysts, a nd tumors may be associated with fetal distress or malformations, Colo r Doppler ultrasound (US) is useful in the identification and evaluati on of structural abnormalities of the cord, By allowing measurement of blood flow velocity in the umbilical artery, duplex Doppler US may pr ovide additional information in the evaluation of intrauterine growth retardation and twin-twin transfusion syndrome.