Fused umbilical arteries

(A, B, and C) Fused umbilical arteries.
(A) Simultaneous view of an umbilical cord with a fused umbilical artery. The segment closest to the placenta shows a two-vessel cord, while the segment closest to the fetus shows the normal three-vessel cord.
(B) Dual view of the umbilical cord in a fetus with fused umbilical arteries shows a segment with three vessels (left) and two vessels (right). At delivery, the exact site at which the arteries fused is shown. The Wharton's jelly was removed after fixation with formalin.
(D and E) Dual view of the umbilical cord from a fetus with fused umbilical cord. The umbilical cord has two vessels. However, the normal two intraabdominal arteries are depicted with color Doppler ultrasound.