318: Umbilical cord occlusion (UCO) via laser in obligate lethal discordant anomalous monochorionic multiple gestations before and after 20 weeks of gestation

Laser photocoagulation of the umbilical cord is often not considered an option for selective UCO after 20 weeks gestation because of cord thickness. We compared outcomes after laser UCO (L-UCO) at 20 weeks gestational age. We examined all patients with monochorionic-diamniotic twins and higher-order multiples (monoamniotics excluded) that underwent L-UCO at our facility between 2006 and 2014. Statistical analysis was performed using the Fisher’s exact and Kruskal-Wallis tests as appropriate. Of 43 L-UCO cases, 21 (48.8%) had a gestational age > 20 weeks: 11 cases (25.6%) had a discordant anomalous twin, and 32 cases had twin reversed arterial perfusion syndrome (TRAP). Most cases were twins (n=34, 79.1%). Perioperative characteristics and outcomes did not differ between those who were operated on at 20 weeks of gestation (table). L-UCO is a safe and effective procedure with similar perinatal outcomes beyond 20 weeks compared to earlier gestation.