(147) Laser Energy and Perinatal Outcomes Following Fetoscopic Laser Photocoagulation for Twin-to-Twin Transfusion Syndrome

Twin-to-twin transfusion syndrome (TTTS) affects monochorionic twin pregnancies and is treated with fetoscopic laser photocoagulation (FLP), the standard of care. However, FLP may be associated with adverse perinatal outcomes. We aimed to evaluate the association between the amount of laser energy used during FLP and perinatal outcomes in TTTS.


Study Design:

This retrospective cohort study included monochorionic twin pregnancies undergoing FLP for TTTS at a single tertiary center between 2012 and 2024. Total laser energy was analyzed as a continuous variable and dichotomized at 5100 J based on optimal cut-point via Youden’s index. Outcomes included placental abruption, chorioamniotic membrane separation (CAS), preterm premature rupture of membranes (pPROM), and preterm delivery ≤ 32 and ≤ 34 weeks. Bivariate analyses compared outcomes by energy groups. Multivariable logistic regression evaluated the association between increasing laser energy (per 100 J increments) and preterm delivery ≤ 34 weeks while adjusting for preoperative cervical length, gestational age at surgery, postoperative CAS, pPROM, and septostomy.


Results:

Of 496 patients undergoing laser surgery, 245 received < 5100 J and 251 received ≥ 5100 J of laser energy. The higher energy group had a later gestational age at surgery (20.9 vs. 19.4 weeks, p < 0.001) and earlier delivery (30.4 vs. 31.3 weeks, p = 0.02) (Table 1). Deliveries ≤ 32 and ≤ 34 weeks were significantly associated with higher energy use (Table 2). No significant differences were observed between energy groups in rates of CAS, pPROM, or placental abruption. In adjusted multivariate analysis, each 100 J increase in energy was associated with 1% increased odds of delivery ≤ 34 weeks (aOR 1.01, 95% CI 1.00–1.02; p = 0.02).


Conclusion:

Higher laser energy use during TTTS surgery was associated with later gestational age at surgery and with earlier delivery. Each 100 J increase in laser energy independently increased the risk of preterm delivery at ≤ 34 weeks by 1%. Procedural energy use may represent a modifiable factor influencing latency and warrants further investigation.