Background: Hypereosinophilic syndrome is characterized by peripheral
blood eosinophilia and multiple organ system involvement. Only one cas
e in a newborn has been reported. Case: Fetal sonography performed on
a 33-year-old woman at 35 weeks' gestation showed pericardial effusion
and cardiomegaly. The infant was delivered by cesarean at 35 weeks' g
estation because of a worsening of the pericardial effusion. Hematolog
ic studies revealed unexplained hypereosinophilia, and the pericardial
fluid contained a large number of eosinophils. Chromosomal analysis r
evealed trisomy 21. The hypereosinophilia, pericardial effusion, and c
ardiomegaly all resolved after 8 weeks of steroid therapy. Conclusion:
Hypereosinophilic syndrome caused pericardial effusion and cardiomega
ly in a fetus with trisomy 21. (Obstet Gynecol 1998;92:701-2. (C) 1998
by The American College of Obstetricians and Gynecologists.).