Prenatal diagnosis and outcome of multiple pregnancies with reversed arterial perfusion (TRAP-sequence)

Objectives We analyse the prenatal detection and pregnancy outcome of twin reversed arterial perfusion syndrome (TRAP-sequence) in monochorionic twin pregnancies. Methods We included all cases in which the prenatal diagnosis of a TRAP-sequence had been established and reviewed the prenatal, obstetrical, and pathological records of the acardiac twin as well as the neonatal/pediatric records of the donor twin. Minimal follow-up for the donor twin after birth was 6 months. Results We detected six cases of TRAP-sequence in 412 examined monochorionic multiple pregnancies (incidence 1.46%) Mean gestational age at diagnosis was 20.4 (13.1-28.0) gestational weeks. All donor twins survived without detectable mid- or long-term sequelae. There was neither missed prenatal diagnosis nor a false-positive diagnosis of TRAP-sequence. Mean birthweight of the acardiac twins was 1,400 g (830-2800 g). There was an uneventful medical history in the maternal records of all included women. Fetal karyotype was available for 5/6 twin-pairs, all revealing a normal distribution of the chromosomes. All acardiac twins had post-mortem examination with specification of the subtypes of acardiac twin displaying 3/6 acardius acephalus, 2/6 acardius amorphus, and 1/6 acardius anceps. Conclusions The antenatal diagnosis of TRAP-sequence is feasible and can be established during the first-trimester- screening. The discrimination of the adequate time to end the pregnancy, though a crucial concern, remains a challenging question. Future studies should address this topic.