Antenatal factors at diagnosis that predict outcome in twin-twin transfusion syndrome

Abstract

Objective: We sought to identify clinical factors at diagnosis that predict outcome in twin-twin transfusion syndrome. Study Design: In this retrospective series 23 patients with twin-twin transfusion syndrome were seen in a tertiary referral fetal medicine center over a 3-year period. Ten antenatal factors were assessed to determine their ability to predict outcome by use of ordered logistic regression. These factors were the following: (1) absent or reversed end-diastolic flow in the umbilical artery, nonvisible bladder, anhydramnios, and estimated fetal weight of <3rd percentile in the donor; (2) pulsatile umbilical vein, either absent or reversed end-diastolic flow in the ductus venosus, or both, and tricuspid–mitral valve regurgitation in the recipient; and (3) gestational age at presentation, estimated fetal weight discordancy, absent arterioarterial anastomosis, and spontaneous rupture of the membranes or cervical change as pregnancy factors. Management comprised serial amnioreduction (n = 10), selective feticide (n = 5; 4 also had amnioreduction), septostomy (n = 4; 1 also had amnioreduction), and delivery (n = 2). Two patients miscarried before treatment. Results: The chance of survival of both twins fell and double deaths increased linearly with increasing number of adverse factors ( P = .026). A low chance of survival was independently associated with absent or reversed end-diastolic flow in the donor umbilical artery ( P = .02) and with a pulsatile umbilical vein or absent or reversed end-diastolic flow in the ductus venosus ( P = .03) of the recipient. The probability of at least one twin surviving was only 33% if there was absent or reversed end-diastolic flow in the donor umbilical artery or 37% when abnormal venous recordings were seen in the recipient. An arterioarterial anastomosis detected at diagnosis also influenced prognosis, with all twins surviving when an arterioarterial anastomosis was identified ( P = .04). Conclusions: Three factors identified at diagnosis independently predict poor survival in twin-twin transfusion syndrome—absent or reversed end-diastolic flow in the donor umbilical artery, abnormal pulsatility of the venous system in the recipient, and absence of an arterioarterial anastomosis. These may have a role in the counseling of parents and in selecting the appropriate treatment strategy. (Am J Obstet Gynecol 2000;183:1023-8.)