(1085) Risk Factors for PPROM after Fetoscopic Placental Laser Ablation for Twin-Twin Transfusion Syndrome

Preterm prelabor rupture of membranes (PPROM) is a frequent complication after fetoscopic placental laser ablation (PLA) for twin-twin transfusion syndrome (TTTS). Our center previously found no risk factors for PPROM after PLA. Here, we leveraged substantial clinical experience and the dataset of a high-volume TTTS referral center to update these findings.

Study Design:
A secondary analysis of a prospective cohort study was conducted on 983 PLA cases performed at our fetal center (2011 - 2025). Only cases of TTTS were included. Triplet or higher order gestations, monoamniotic twins, terminations, and cases with missing outcome data were excluded. Maternal and perioperative factors were compared between groups. Statistical tests included two-sample t tests, χ2 test, and Fisher’s exact test, where appropriate. Stepwise multiple logistic regression was used to identify clinical factors associated with PPROM.

Results:
Of 843 cases, PPROM complicated 339 (40.2%). The median gestational age (GA) at PPROM was 190 (161, 217) days. Maternal characteristics did not differ between groups. The PPROM group had an earlier GA at PLA (138 [126,151] versus 144 [131, 157] days, p < 0.001), a lower rate of amnioreduction (AR; 85.3% versus 90.8%, p = 0.016), and a higher rate of chorion-amnion separation (CAS; 17.4% versus 6.5%, p < 0.001) than the non-PPROM group. The PPROM group delivered earlier, had higher rates of chorioamnionitis and placental abruption, and had lower rates of dual neonatal survival than the non-PPROM group (Table 1). Stepwise logistic regression yielded a final predictive model that included Hispanic ethnicity, trocar size and entry type, laser energy, AR, cervical length (CL), donor maximum vertical pocket (D MVP), GA at PLA, total anastomoses, and CAS, with significant associations observed for CL, D MVP, GA at PLA, total anastomoses, and CAS (Table 2).

Conclusion:
PPROM complicates 40% of fetoscopic PLA cases for TTTS and contributes to perinatal morbidity. Key risk factors include CL, D MVP, GA at PLA, total anastomoses, and CAS. Underlying mechanisms warrant further investigation.