Outcome of monochorionic twin pregnancies with moderate amniotic fluid discordance adjoining twin-twin transfusion syndrome.

OBJECTIVES This study aimed to assess the perinatal outcome in monochorionic diamniotic (MD) twin pregnancies complicated by amniotic fluid discordance (AFD) adjoining twin-twin transfusion syndrome (TTTS). METHODS An observational study of 84 consecutive MD twin pregnancies complicated by AFD that resembled TTTS was conducted. AFD adjoining TTTS was defined by a maximal vertical pocket of amniotic fluid ≤3 cm in one twin and ≥7 cm in the other excluding TTTS. The study population was divided into two groups, group 1 and group 2, according to positive and absent or reversed end-diastolic flow (AREDF) in the umbilical artery, respectively. RESULTS Fifteen of the 35 (42.9%) group 1 cases and 30 of the 49 (61.2%) group 2 cases progressed to TTTS. The overall survival and intact survival rate in constant AFD that never progressed to TTTS in group 1 was 100% (40/40) and 90% (36/40), respectively. The overall survival and intact survival rate of constant AFD in group 2 with selective intrauterine growth restriction (sIUGR) was 54.2% (13/24) and 41.7% (10/24), respectively, and for those without sIUGR was 64.3% (9/14) and 57.1% (8/14), respectively. CONCLUSIONS Constant AFD with AREDF in the umbilical artery represents an extremely high risk for adverse outcomes regardless of the presence of sIUGR.