(531) Impact of second trimester vaginal bleeding on outcomes in patients undergoing laser for TTTS

Objective: To determine whether second trimester vaginal bleeding is associated with perioperative complications and worse outcomes after laser for Twin-Twin Transfusion Syndrome (TTTS).

Study Design: Retrospective analysis of prospectively collected data from a monochorionic (MC) pregnancy registry at a Level III fetal care center. The records of patients with MC twins that underwent laser for TTTS between 1/2013-1/2024 were reviewed to determine the incidence of second trimester vaginal bleeding prior to the laser procedure. Those without clear documentation of bleeding were excluded. Pregnancy characteristics and outcomes were then compared between patients that had second trimester bleeding versus those that did not using Mann-Whitney U, chi-square, and Fisher’s exact tests, as appropriate.

Results: Of 373 patients that underwent laser over the study period, 359 (96.2%) had clear documentation of whether they had second trimester vaginal bleeding including 30 (8.4%) that did and 329 (91.6%) that did not, respectively. Although demographic characteristics and survival outcomes were similar between groups, patients with second trimester vaginal bleeding had longer median operating room times (61 vs 50 minutes, p=0.032), higher need for amnioexchange (33.3 vs 14.3%, p=0.006), and higher incidence of preterm premature rupture of membranes within 1 week after the laser procedure (16.7 vs 3.3%, p=0.001).

Conclusion: In our cohort, second trimester vaginal bleeding was associated with a higher incidence of perioperative complications surrounding laser for TTTS. This information can be utilized to guide future studies and in counseling patients prior to the laser procedure.