Management of monochorionic twins discordant for structural fetal anomalies

To review the perinatal management and outcomes of monochorionic twin pregnancies (MC) discordant for congenital anomalies (DCA).

Retrospective, study of all MC DCA cases referred to our tertiary referral center from 1997 to 2018. We excluded cases complicated with twin-to-twin transfusion syndrome, twin anemia-polycythemia sequence, twin reversed arterial perfusion sequence or selective intra-uterine growth restriction. Patients were counseled about the possibility of expectant (EM) or interventional management (selective feticide [SF] or termination of the entire pregnancy [TOP]).

One hundred eight of 4157 (2.6%) MC pregnancies were discordant for anomaly. Fifty two of 108 n(48.1%) underwent SF at a mean gestational age of 31.4 ± 5.9 weeks while 52/108(48.1%) opted for EM. Livebirth rate of the healthy co-twin was similar between the two groups (SF: 88.5% vs EM: 82.7%, P = .87). In the SF group, six healthy co-twins (6/52, 11.5%) died 5.3 ± 3.1 days after SF of the abnormal co-twin. In the EM group, in-utero demise of the abnormal twin occurred in 9 of 52 (17.3%) of the cases and was followed by the spontaneous demise of the healthy co-twin in 4 of 9 (44.4%) of these cases.

Selective feticide does not seem to significantly alter survival of the healthy co-twin compared to EM.