The investigators hypothesize that treatment of twin-twin transfusion syndrome (TTTS) using sequential laser photocoagulation of communicating vessels (SQLPCV) over the predominant method, selective laser photocoagulation of communicating vessels (SLPCV), may provide vascular stability to the donor fetus. The primary objective is to evaluate the perinatal outcome, specifically, donor intrauterine survival of TTTS managed by SQLPCV vs. SLPCV in a prospective, randomized trial.

Inclusion Criteria:

• Gestational age: 16 weeks, 0 days to 26 weeks, 0 days.

• Confirmed TTTS patients, who by definition meet the following sonographic criteria:

  • Single placenta.
  • Polyhydramnios: maximum vertical pocket ≥ 8 cm in the recipient twin, prior to amniodrainage.
  • Oligohydramnios: maximum vertical pocket ≤ 2 cm in the donor twin, prior to amniodrainage.
  • Thin dividing membrane (absence of twin peak sign) or absence of dividing membrane (monoamniotic).
  • Same gender, if visible.
  • Quintero Stages 1-4.

• Patients choosing laser therapy that have undergone prior therapeutic amniocentesis may be included.

• Patients with an anterior placenta may be included.

• Triplet gestations with two or three fetuses sharing the same placenta may be included.

• Patients must be able to give written informed consent.

Exclusion Criteria:

• Patients unable or unwilling to participate in the study or to be followed up.
• Patients unable to give written informed consent.
• Presence of major congenital anomalies that may not warrant surgery.
• Known unbalanced chromosomal complement.
• Prior intentional septostomy (purposely making a hole in the dividing membrane).
• Ruptured membranes.
• Chorioamnionitis.
• Abnormal intracranial ultrasound findings of either fetus to include, but not limited to: intraventricular hemorrhage, porencephalic cysts, hydrocephalus, Dandy-Walker syndrome, holoprosencephaly and agenesis of the corpus callosum. Isolated ventriculomegaly (atrium 10-19 mm) may or may not be used as exclusion criteria.
• Placental abruption.
• Active labor.
• Patient unwilling to receive blood products.
• Recipient twin with a middle cerebral artery peak systolic velocity > 1.5 multiples of the median (indicative of fetal anemia).
• Any other patient deemed inappropriate for the study by the principal investigator.