Sonographic umbilical coiling index (UCI) and ductus venosus a-wave velocity in early pregnancy

Introduction: The cause of the umbilical cord (UC) coiling is still a matter of debate. This helical structure is fully developed as early as the eight weeks of gestation and the number of coils observed in early gestation are roughly the same as in late gestation. It has been shown, that the UCI decreases significantly during gestation due to a progressive lengthening of the UC. These changes of the UCI may be also triggered by hemodynamic forces. Material and Methods: Consecutive patients referred for a sonographic evaluation during the early second trimester (