TRAP sequence in an acardiac twin.

CASE REPORT: The authors present a case of an acardiac twin gestation diagnosed sonographically at 20 weeks with evidence of twin reversed-arterial perfusion (TRAP) sequence. The acardius appeared to be less than half the estimated weight of the pump twin. The acardius was identified as an amorphous mass, without extremities. The parents chose expectant management rather than surgical intervention. Observation by serial sonographic and color Doppler evaluation was performed. At 34 weeks, a healthy infant was delivered by cesarean section after showing signs of fetal congestive heart failure (CHF). The acardius was 2/3 the size of the infant at delivery.

CONCLUSION: Expectant management with close antepartum surveillance deserves consideration in cases of monozygotic twins with TRAP sequence. Neonatal mortality of the pump twin diagnosed antenatally may be considerably less than reported.