Prenatal sonographic diagnosis of pseudomonoamniotic twins: Two-case series

Targeted evaluation of the dividing membrane at the umbilical cord insertion sites may improve the detection of spontaneous PMA. Sonographic manifestations of dividing-membrane rupture include the multilayer folding sign, absence of the dividing membrane, 1 fetus entering the amniotic sac of the co-twin, and umbilical cord entanglement. The multilayer folding sign may be an early indicator of the rupture dividing membrane. Complications resulting from dividing-membrane rupture warrant heightened vigilance, especially amniotic band syndrome and cord entanglement, both of which are associated with adverse perinatal outcomes.