Randomized Clinical Trial: Expectant Management vs Laser Treatment of Monochorionic Twins With Severe Selective Intrauterine Growth Retardation and Absent or Reverse Diastolic Flow in the Umbilical Artery

Randomized Clinical Trial: Expectant Management vs. Laser Treatment of Monochorionic Twins With Severe Selective Intrauterine Growth Retardation And Absent or Reverse Diastolic Flow in the Umbilical Artery

Intrauterine growth retardation (IUGR) occurs in approximately 3 to 10% of singleton pregnancies, in 9.1% of all twins and 9.9% of monochorionic twins. IUGR in monochorionic twins typically affects only one of the fetuses (selective IUGR or SIUGR). Spontaneous demise of the SIUGR twin can occur, and may result in concomitant demise (up to 40% risk) or severe neurologic handicap (up to 30% risk) of the other twin. These complications result from exsanguination of the appropriately grown (AGA) twin into the demised SIUGR twin through placental vascular communications.

Because the adverse effects to the AGA twin of the spontaneous demise of the SIUGR twin are mediated through placental vascular anastomoses, we have proposed obliterating such anastomoses via endoscopic fetal surgery. We have developed a technique that allows us to identify the vascular anastomoses present in monochorionic placentas. Briefly, deep AV communications are identified on the surface of the placenta by noting that the terminal end of the artery of one of the fetuses does not have a corresponding returning vein to the same fetus. We have speculated that the separation of the circulations may be of benefit in monochorionic twins affected by SIUGR by preventing the adverse effects that may result from the spontaneous demise of the IUGR twin. Our goal is to evaluate with a randomized clinical trial the outcome of SIUGR managed either expectantly or with SLPCV.

Study procedures will begin with confirmation of the diagnosis and screening criteria at the Qualified Clinical Center. The patient will sign the appropriate consents and then be randomized to her treatment group. Enrollment data will be submitted to the research coordinator in Coordinating Center in Tampa. Expectant management patients will be treated by the referring physicians. Laser patients will be treated at Coordinating Center in Tampa General Hospital or qualified laser center. They may return to the referring center for follow-up. After delivery, outcome data will be sent to the research coordinator in Coordinating Center in Tampa.

Inclusion Criteria:

• Gestational age 16--24 weeks
• Sonographic evidence of monochorionicity: single placenta, same gender, absent twin-peak sign
• Diagnosis of IUGR present in one twin (fetal weight at or below the 10th percentile for gestational age)
• Persistent absent or reverse-end diastolic flow in the umbilical artery in the SIUGR twin
• Able to provide written informed consent

Exclusion Criteria:

• Patients unwilling to participate in the study, provide consent, or to be followed up
• Presence of twin-twin transfusion syndrome (TTTS) defined as a maximum vertical pocket (MVP) of ≤2 cm in one sac and MVP of ≥8 cm in the other sac.
• Presence of major congenital anomalies (anencephaly, acardia, spina bifida) or intracranial findings in either twin: IVH, porencephalic cysts, ventriculomegaly or other findings suggestive of brain damage.
• Both twins are <10th percentile
• Diastolic flow or intermittently absent end-diastolic flow in the umbilical artery in the SIUGR twin
• Unbalanced chromosomal complement (if known).
• Ruptured or detached membranes
• Placental abruption
• Chorioamnionitis
• Triplets
• Active labor
• Jehovah's witness
• Any other patient deemed inappropriate for the study by the principal investigator
• Placenta previa