When One Twin Dies in Utero, the Other's Long-Term Prognosis Is Poor

When one twin dies during the second or third trimester of a monochorionic, monozygotic twin pregnancy, the prognosis for the surviving twin is poor. Because there are anastomoses within the monochorionic placenta, thromboplastic material might pass from the dead twin to the circulation of the living twin, causing tissue necrosis by direct embolization or by activation of intervascular coagulation. In addition, acute blood loss into the dying twin through the anastomoses may lead to hypotension and hypoxic-ischemic damage in the survivor. Outcome data on surviving twins have generally been limited to the neonatal period. These investigators examined longer-term outcomes (range, 4 months to almost 20 years) among 18 surviving twins of monoch…