P12.12: Relationship between single umbilical artery in twin pregnancies and pregnancy outcome

Abstract

manifestations of the underlying hemodynamic imbalance may be present as early as the first trimester of gestation and may have a profound impact on the development of the UC angioarchitecture. Methods: Twenty four consecutive monochorionic twins with TTTS were included into the study. The length of one complete umbilical vascular coil (distance between the right outer surface of consecutive arterial coils) was measured in a longitudinal section of the UC. The coiling index (CI), defined as the reciprocal value of that measurement, was calculated. The UC coiling pattern was classified as normal or abnormal [uncoiled, hypocoiled (CI 90th centile)] according to local reference ranges. Atypical (uncoordinated, supercoiling) coiling was classified according to Raio et al. (ISUOG 2003, OC 205). Results: Nine (37.5%) and 8 (33.3%) cases were treated with endoscopic laser coagulation and amnionreduction, respectively. In the remaining 7 (29.2%) cases, no treatment was undertaken. The surviving rate was 72.2%, 56.3%, and 21.4% in the laser, amnioreduction and no treatment group, respectively. The donor twin showed in 22 (91.7%) cases a less twisted UC than the recipient twin. Of these, 12 (54.5%) were uncoiled and 5 (22.7%) hypocoiled. On the other hand, the UCs of recipient twins were characterized by a high percentage of atypical [4 (16.7%) with supercoiling, and 8 (33.3%) with uncoordinated coiling], and abnormal coiling patterns [4 (16.7%) with hypercoiling, 2 (8.3%) hypocoiling]. Only 13 (27.1%) cases had a CI within normal ranges for gestational age. In one case informations on UC angioarchitecture was available from the first trimester and the UCs were uncoiled and atypical, respectively. Conclusions: Monochorionic twins with TTTS have different UC coiling patterns.