EP20.11: Ultrasound Labelling of Twins: Could the Placental Cord Insertion Be Useful?

To define if the visualisation of the cord insertion (CI) on the placenta could improve the accuracy of twins labelling in case of same sex and single placental mass. A non consecutive series of dichiorionic twin pregnancies with the same fetal sex and fused placentas or monochiorionic twin gestations were recruited for the study purpose. A single operator had been performing serial scans either monthly or fortnightly according to our local protocol. The patients were randomly assigned to two groups according to the following twins labelling method: presenting twin (PT) or Cord insertion (CI) on the placenta. In the CI group the CI was described in terms of relative position of one cord compared with the other (right-left, fundal-low). Only uncomplicated cases submitted by the same operator to 3 or more serial scans were included in the study. We defined “twins switch” (TS) the assignment of the biometric set of one twin to the other in one of the follow up scans. Incidence of TS was compared among the groups. We enrolled 170 patients, of these 82 were assigned to the PT labelling group cases and 88 to the CI group. The incidence of TS was noted to be significantly higher in the PT group compared with the CI group (19.51% vs 4.54% p=0.002). The ultrasound evaluation of the cord insertion on the placenta seems to improve the accuracy of twins labelling in case of twins with same sex and a single placental mass.