Umbilical cord entanglement is the leading cause of fetal mortality in monoamniotic twin pregnancies and a pseudo monoamniotic environment. Published methods for detecting this complication include color Doppler and pulsed Doppler sonography; however, no method provides an absolute diagnosis. In this case, we report the diagnosis of umbilical cord entanglement using dual-gate Doppler imaging. A 35-year-old woman was referred to our hospital at 28 weeks of gestation for prenatal management because of diagnosis of a monochorionic diamniotic twin pregnancy with spontaneous septostomy of the dividing membranes. Each fetus displayed normal fetal growth without obvious discordance and anatomical abnormalities. However, the dividing membrane was not detected, and an entangled cord was suspected. Dual-gate Doppler examination was carried out. Two regions of interest were considered at different areas of the umbilical arteries, and when each Doppler image showed two different heart rates at the same time, we considered this to be evidence of umbilical cord entanglement. Cesarean section was performed at 32 weeks of gestation and twins were delivered. The delivered umbilical cords had sixfold entanglement. In this case, dual-gate Doppler seems to have been more accurate than conventional single-gate Doppler for the diagnosis of cord entanglement because we confirmed two different heart rates at the same time with dual-gate Doppler.
Keywords: Monoamniotic twin; Monochorionic diamniotic twin; Umbilical cord entanglement.