Fetoscopic Selective Laser Photocoagulation in Twin-Twin Transfusion Syndrome

Inclusion Criteria: * Both twins are alive * TTTS diagnosed prior to 22 weeks gestation * Monochorionic diamniotic gestation * Like sex twins * Single placental mass * Thin intertwin membrane * Oligohydramnios in donor twin (deepest vertical pocket of ≤ 2 cm) * Polyhydramnios with deepest vertical pocket of \> 8 cm with or without Doppler or echocardiographic changes in the recipient twin (deepest vertical pocket of \> 6 cm if previous amnioreduction) * Decompressed bladder in donor not seen to fill during the ultrasound examination (stage II, III, or IV), unless Doppler velocimetry changes (absent end-diastolic umbilical artery flow, abnormal ductus venosus waveform), and/or echocardiographic changes (valvular insufficiency, ventricular hypertrophy) are already present * No associated structural abnormalities * No sonographic evidence of CNS injury at time of entry * No preterm labor * No maternal medical contraindication to anesthesia or surgery Exclusion Criteria: * Failure to meet all inclusion criteria * TTTS presenting after 22 weeks gestation * Randomization after 24 weeks gestation * Cervical length \< 2.0 cm post initial * Presence of cervical cerclage * Uterine anomaly * Refusal to accept randomization * Unable to pursue prenatal care at an approved center coordinated by one of the participating institutions * Unable to pursue postnatal evaluation at a NICHD Neonatal Research Network Institution