Objective: Our purpose was to investigate the use of color flow Doppler ultrasonography to identify umbilical cord entanglement.
Study design: Our case series consisted of three monoamniotic twin gestations. Color flow Doppler was used prospectively to study the umbilical cords.
Results: Apparent "branching" of the umbilical artery, with evidence of two different heart rates in the two segments of the branch, was seen in all cases. Compression of the umbilical vein was identified by extremely high blood velocity.
Conclusions: Color flow Doppler is useful in the identification of umbilical cord entanglement in monoamniotic twin pregnancies and may provide a method of monitoring the fetuses for evidence of cord compression.