UMBILICAL ARTERY FLOW VELOCITY WAVE-FORMS IN MONOAMNIOTIC TWINS WITH CORD ENTANGLEMENT

Background: Monoamniotic twins with ultrasonographic evidence of umbil ical cord entanglement present a management challenge in the antepartu m period. Cases: We report two pregnancies with monoamniotic twins and ultrasonographic evidence of cord entanglement in which longitudinal Doppler now velocity waveforms of the umbilical and middle cerebral ar teries were obtained. A notch in the umbilical artery velocity wavefor m was noted in one twin member at 33 weeks' gestation and in both twin members of the other pregnancy at 31 weeks' gestation. Worsening of t he umbilical artery velocity waveform notch with advancing gestation w as noted in one fetus. Conclusion: The presence of a notch in the umbi lical artery velocity waveform may reflect hemodynamic alterations in the fetal-placental circulation secondary to narrowing of the umbilica l vessels involved in cord entanglement. This Doppler finding may be u seful in the antepartum management of these pregnancies.