P360: Prenatal umbilical cord morphometry in monochorionic twins with twin-to-twin-transfusion syndrome

Umbilical cord (UC) calibre variations have been reported to be an initial sign of amniotic fluid and fetal hemodynamic compromise. Since twin-to-twin transfusion syndrome (TTTS) is a condition characterized by severe amniotic fluid and fetal hemodynamic alterations we sought to investigate the UC morphometry of twins affected by TTTS. During a 3-year period, the UC biometry was assessed prospectively in 163 twin pregnancies. The sonographic cross-sectional area of the UC was calculated in a free floating loop of the UC. A TTTS was defined as the presence of a poly-/oligoamnios sequence with always a visible bladder of the recipient twin and an empty bladder of the donor twin. The UC was defined lean or large when its cross-sectional area was below the 10th or above the 90th centile for gestational age, respectively. Only the first UC measurement was used for statistical purposes. Of the 163 multiple pregnancies evaluated, 63 (38.7%) were monochorionic twins. Among these 17 (27%) developed a TTTS. Two cases were excluded because of incomplete data. The incidence of a lean UC was significantly higher in donor twins than in acceptor twins [12/15 (80%) vs. 1/15 (6.7%); p < 0.0001]. On the contrary, a large UC was found significantly more often in acceptor than in donor twins [9/15 (60%) vs. 1/15 (6.7%); p < 0.01]. The UC morphology is dramatically different in monochorionic twins affected by TTTS. It remains to be explored whether the difference of the UC area is already present in the early phase of the disease.