Natural history of twin disruption sequence.

Intrauterine death of one fetus in a monochorionic twin pregnancy is associated with high morbidity and mortality in the surviving co-twin. Thromoboplastic material from the dead twin may pass to the circulation of the living twin via placental anastomoses and cause tissue necrosis by direct embolization or by activating intravascular coagulation. Alternatively, acute blood loss into the dying twin through placental anastomoses may result in hypotension and hypoxic-ischemic damage to cerebral and visceral tissue in the surviving twin. The resulting clinical picture is referred to as twin disruption sequence. Affected twins have rarely been followed beyond the neonatal period and the long-term development of such children is unknown. Here, we present a natural history and neurological assessment of 18 patients with twin disruption sequence, whom we have followed over several months to years.