Clinical History.—Twins were born to a 32-year-old, gravida 2, para 1 woman at 36 weeks' gestation by spontaneous vaginal delivery. The placenta was monochorial. Twin A weighed 2,126 gm with Apgar scores of 9 and 10 initially. Shortly after birth she was noted to be markedly pale and dyspneic with bradycardia and diffuse hypotonia. Because the initial hemoglobin level was 6.2 gm and the hematocrit reading 18%, the patient was transferred to the University of Miami, Jackson Memorial Medical Center, Neonatal Intensive Care Unit, where she was found to be grossly hydropic. Despite multiple transfusions the child died at 18 hours of age.
Twin B weighed 2,353 gm, had Apgars of 5 and 8, respectively, and was noted to be markedly plethoric with grunting and mild respiratory distress. The hemoglobin level was 23 gm and the hematocrit reading 73%. The infant was treated with plasmapheresis and phototherapy for hyperbilirubinemia.