Twin-reversed arterial perfusion sequence in a triple monochorionic pregnancy with two direct pump fetuses results in significant cyclic Doppler waveform.

We report a case of a twin-reversed arterial perfusion (TRAP) sequence complication in monochorionic triplets, in which both normal fetuses were directly connected to the umbilical cord of the acardiac fetus, thus both acting as a pump twin. Doppler ultrasound showed a significant waveform pattern with two superposed systolic waveforms in the same vessel. After birth, placental findings confirmed the existence of two direct pump twins. The Doppler pattern described here may be of help to distinguish the existence of two pump twins in a triplet monochorionic pregnancy with TRAP.