Impact of preoperative second-trimester vaginal bleeding on operative factors and outcomes in patients undergoing laser for twin-twin transfusion syndrome.

INTRODUCTION: Second-trimester vaginal bleeding has been associated with increased risk for preterm delivery after laser for twin-twin transfusion syndrome (TTTS), but its incidence and impact on operative factors and other outcomes is unknown. METHODS: A retrospective analysis of prospectively collected data from a monochorionic (MC) pregnancy registry at a Level III fetal care center was conducted. The records of patients with MC twins that underwent laser for TTTS between January 2013 and January 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 who had second-trimester bleeding versus those who did not using Mann-Whitney U, chi-square, and Fisher's exact tests, as appropriate. RESULTS: Of 373 patients who underwent laser, 359 (96.2%) had clear documentation of whether they had second-trimester vaginal bleeding or not, including 30 (8.4%) who did and 329 (91.6%) who did not. 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 min, 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 used to guide future studies and in counseling patients prior to the laser procedure.