1. Tufts University School of Medicine, Boston, MA, USA;
2. Division of Newborn Medicine, Department of Pediatrics, Floating Hospital for Children at Tufts Medical Center, Boston, MA, USA;
3. Department of Public Health and Community Medicine, Tufts University School of Medicine, Boston, MA, USA;
4. Perinatal Neuroepidemiology Unit, Hannover Medical School, Hannover, Germany