Prenatal spontaneous disruption of the dividing membrane in monochorionic diamniotic twins detected at the time of fetoscopic laser photocoagulation.

Spontaneous antepartum rupture of the dividing membrane occurring in monochorionic diamniotic twins (MD twin) is an extremely rare complication and difficult to diagnose prenatally. We present a case of pseudo-monoamniotic twins derived from an MD twin gestation, which was suspected by ultrasound and was confirmed by antepartum fetoscopy. A 28-year-old woman, gravida 1, para 1 at 24 weeks of gestation was referred because of suspected polyhydroamnios in an MD twin. Ultrasound suggested twin-twin transfusion syndrome stage III, spontaneous rupture of the dividing membranes and cord entanglement. Fetoscopic laser photocoagulation (FLP) was performed using the Nd:YAG laser on 12 placental vascular connections. Fetoscopy revealed the spontaneous rupture of the dividing membrane and cord entanglement. The remainder of the pregnancy was managed as a monoamniotic twin gestation. Elective cesarean section was performed at 32 weeks of gestation following antenatal steroids and concordantly grown healthy male infants were delivered.