Placental dichotomy: a hint in twin anemia polycythemia sequence.

BACKGROUND

Monochorionic pregnancies are a significant part of the workload in diagnostic imaging, and must be assessed frequently for the detection of twin-twin transfusion syndrome. Recognizing placental dichotomy at the time of routine fetal cerebral artery Doppler screening is important for alerting the clinician to potential twin anemia polycythemia sequence, an important subset of feto-fetal transfusions.

CASE: A 36-year-old multigravid woman with a twin pregnancy delivered at 33 weeks' gestation after fetal distress was identified. Twin anemia polycythemia sequence was diagnosed after delivery. Regular prenatal ultrasound scans had not identified oligo- or polyhydramnios. Retrospective assessment of the ultrasound images of the placenta showed marked dichotomy, with the anemic twin's portion being hyperechogenic.

CONCLUSION

Identification of placental dichotomy, in addition to screening with cerebral Doppler flow studies, may lead to earlier identification of twin anemia polycythemia sequence and improved outcomes.