Prevalence of placental dichotomy, fetal cardiomegaly and starry‐sky liver in twin anemia–polycythemia sequence

Objective To investigate the prevalence of three additional ultrasound markers, placental dichotomy, cardiomegaly and ‘starry‐sky’ liver, in monochorionic twin pregnancy with twin anemia–polycythemia sequence (TAPS). Methods All monochorionic twin pregnancies, diagnosed antenatally with TAPS at our center between 2006 and 2019, were reviewed retrospectively for the presence of placental dichotomy, cardiomegaly in the donor twin and a starry‐sky liver in the recipient twin. TAPS was diagnosed based on delta middle cerebral artery (MCA) peak systolic velocity (PSV) > 0.5 multiples of the median. The primary outcome was the prevalence of placental dichotomy, cardiomegaly, starry‐sky liver and at least one of these markers in both spontaneous and post‐laser TAPS. The secondary outcome was the prevalence of these ultrasound markers according to the antenatal stage of TAPS. Results A total of 91 monochorionic twin pregnancies with TAPS were eligible for analysis. Placental dichotomy was observed in 44% (40/91) of TAPS cases. A total of 70% (64/91) of the TAPS donors developed cardiomegaly and a starry‐sky liver was identified in 66% (53/80) of the TAPS recipients. The prevalence of cardiomegaly and starry‐sky liver was roughly comparable between spontaneous and post‐laser TAPS (69% (33/48) vs 72% (31/43) and 64% (25/39) vs 68% (28/41), respectively). Pregnancies with spontaneous TAPS showed a higher prevalence of placental dichotomy compared with post‐laser TAPS (63% (30/48) vs 23% (10/43)). At least one of the three ultrasound markers was detected in 86% (78/91) of TAPS cases, meaning that 14% (13/91) of cases presented solely with discordant MCA‐PSV values. There was a trend towards increased prevalence of all three ultrasound markers with increasing antenatal TAPS stage. Conclusions Placental dichotomy, fetal cardiomegaly and a starry‐sky liver are commonly found in TAPS pregnancy. Investigating the presence of these ultrasound markers can be of additional help in improving antenatal detection of TAPS in monochorionic twin pregnancy. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.