Objective: Our objective was to document the anatomy, flow pattern, and time of closure of the ductus venosus in healthy full-term neonates.
Subjects and methods: We examined the ductus venosus in 73 neonates by using gray-scale sonography, color flow imaging, and duplex Doppler sonography. Each neonate was examined 1-2 days after birth, 6-7 days after birth, and then every 3-4 days until closure was confirmed or the neonate was 18 days old. The length, width, and color flow and duplex Doppler characteristics of the ductus were noted. Closure of the ductus at 6-7 days after birth was examined with respect to birth weight, hemoglobin level, and gestational age.
Results: The ductus venosus, extending from the left portal vein to the inferior vena cava, was identified with all three techniques. The ductus was patent in all 73 neonates 1-2 days after birth. It was still patent in 41 (68%) of 60 neonates reexamined 6-7 days after birth and in two of three neonates (11% [7/60]) reexamined 17-18 days after birth. Blood flow within the ductus was cephalic, in a constant venous waveform. Initial flow velocity ranged from 0.15 to 0.70 m/sec and decreased consistently in subsequent examinations. There was no significant difference in birth weight, hemoglobin level, or gestational age between the group whose ductus was closed and the group whose ductus was open at 6-7 days after birth.
Conclusion: The ductus venosus in neonates is consistently detectable on sonography. It is patent in a greater percentage of neonates, and for a longer time, than was previously shown with conventional radiographic studies with angiography.