A case of discordant monochorionic diamniotic twin with umbilical cord entanglement after spontaneous rupture of the dividing membrane.

Spontaneous antepartum rupture of the dividing membrane in monochorionic diamniotic twins with discordancy is extremely rare. The rupture is difficult to diagnose prenatally and has a poor outcome. The authors report a case of cord entanglement after spontaneous rupture of the dividing membrane within discordant monochorionic diamniotic twins. The subject was a 30-year-old woman pregnant with discordant monochorionic diamniotic twin at 27+4 gestational weeks. The relatively thin dividing membrane was sound until it passed parallel to the two umbilical cords where it then became ill-defined. The patient was managed cautiously due to the possibility of spontaneous rupture of the dividing membrane and potential cord entanglement. Upon delivery at 29+3 weeks due to fetal compromise, the patient presented with a monochorionic diamniotic placenta, a remnant of the disrupted dividing membrane, and entangled umbilical cords. The authors report this subject with literature review.