Vanished twin and fetal alcohol syndrome in the surviving twin. A case report.
BACKGROUND: The diagnosis of twin pregnancy can be made early in pregnancy by ultrasonography (US). Follow-up examination occasionally demonstrates the disappearance of one of the twins. CASE: A twin disappeared on US examination; the surviving twin exhibited signs of fetal alcohol syndrome and other congenital anomalies, accompanied by a placental form of fetus papyraceus. CONCLUSION: Early US examination is useful for diagnosing multiple gestation. However, a follow-up examination is required to alert the clinician to the disappearance of one twin. Careful examination of the placenta may document fetal remnants. In this case a small, atretic nodule on the placental surface was evidence of the vanished twin.