Fetoscopic laser ablation of placental vascular anastomoses is an intrauterine therapy targeting the source of twin-to-twin transfusion syndrome (TTTS). Our patient had successful laser treatment, with resolution of stage II TTTS, suggesting closure of all significant anastomoses. After an uneventful pregnancy course, she elected a trial of labor. Following spontaneous onset of labor, acute intrapartum twin-to-twin transfusion was suspected, suggested by sinusoidal heart rate changes, confirmed postdelivery by twins' complete blood counts. The potential risks of labor with prior fetoscopic laser ablation are reviewed in the context of current knowledge about placental architecture in TTTS.
