1. Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
2. Division of Hematology, Oncology and Stem Cell Transplant, Ann and Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
3. Department of Pediatrics, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
4. Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, Pennsylvania.
5. Division of Pediatric Oncology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.