Diamniotic Omphalopagus Conjoined Twins in a Diamniotic Pregnancy

Objective: To present antepartal diagnostic findings including 2D/3D ultrasonography in a rare case of conjoined twins with diamniotic placentation. Methods: In ultrasonographic examination, a communicating structure containing solid and cystic components together with cord vessels was found between the fetuses. The long axes of the fetuses were not parallel and they moved independently. Bladder configurations were absent. A fetal membrane from the chorioidal plate was imaged. Results: Postmortem pathological examination revealed that the twins were conjoined by way of fused cloacal exstrophy and omphalocele, and the separate amniotic cavities communicated via a fused allantoic cavity. The placenta was monochorionic and diamniotic. DNA analysis of the twins and the placenta confirmed the monozygotic origin. Conclusion: Visualization of the amniotic membrane does not rule out conjoined twins in rare cases of monochorionic twin pregnancies. Copyright (C) 2009 S. Karger AG, Basel