Monochorionic monoamniotic multiple gestations with twin-twin transfusion syndrome: case series of 6 laser surgery patients and management considerations.

Introduction: Twin-twin transfusion syndrome (TTTS) is a rare occurrence in monochorionic monoamniotic (MCMA) multiple gestations. Clinical management remains challenging due to increased technical difficulty of selective laser photocoagulation of communicating vessels and limited data regarding outcomes after laser surgery. Our objective is to present outcomes of monochorionic monoamniotic multiple gestations with TTTS who underwent laser surgery.

Methods: Retrospective study of all MCMA multiple gestations between 2006 to 2024 across two institutions treated with laser surgery for TTTS. Results are presented as median (range).

Results: Out of 1078 laser surgeries for TTTS, 6 (0.6%) were performed in MCMA gestations: 5 monochorionic monoamniotic twins and 1 dichorionic diamniotic triplet. The gestational age (GA) at diagnosis was 19.5 (16.9-22.3) weeks. Quintero Stage was II (n=3) and III (n=3). The placental cord insertion sites were proximal (< 4 cm apart) in 2 (33%) cases. Despite increased technical difficulty, laser surgery was successfully completed in all cases. One case required more than 1 trocar entry to adequately evaluate the complex vascular equator. The GA at delivery was 27.2 (23.6-31.7) weeks. Indications for delivery included placental abruption (n=2; 33%), fetal growth restriction (n=2; 33%), chorioamnionitis (n=1; 17%), and elective (n=1; 17%). Dual 30-day survivorship occurred in 5 (83%) patients and dual demise occurred in 1 (17%) patient.

Conclusion: Laser surgery for TTTS in MCMA multiple gestations is technically feasible. However, outcomes are guarded compared to monochorionic diamniotic twins. Additional studies are needed to investigate the optimal management of TTTS in monoamniotic multiple gestations.