The use of amniotic fluid discordance in the early second trimester to predict severe twin-twin transfusion syndrome

Abstract

Introduction: The appropriate effectiveness of inter-twin amniotic fluid discordance (AFD) in the early second trimester for the prediction of severe twin-twin transfusion syndrome (TTTS) was evaluated. Materials and Methods: The largest AFD between 16 and 18 weeks' gestation was analyzed in correlation with TTTS development defined by polyhydramnios with a maximum vertical pocket (MVP) ≥8 cm combined with oligohydramnios with a MVP ≤2 cm using the receiver operating characteristics curve. All pregnancies were stratified according to an AFD cutoff, and perinatal outcomes were compared between two groups. Results: A total of 223 twin monochorionic pregnancies met the inclusion criteria and 20 patients (8.9%) developed TTTS. An AFD ≥4 cm was calculated to be the optimal point of demarcation to predict subsequent TTTS. The sensitivity and specificity of this AFD cutoff for the development of TTTS were 70 and 97%, respectively. An AFD ≥4 cm was associated with a significantly increased risk of the development of TTTS (70 vs. 2.9%; p < 0.01). Those pregnancies with AFD tended to deliver at an earlier gestational age and were also significantly associated with intrauterine fetal deaths. Discussion: The AFD between monochorionic diamniotic twins in the early second trimester may be useful for the prediction of severe TTTS development.