1. Department of Nutritional Sciences; The Pennsylvania State University; University Park PA USA
2. Division of Maternal-Fetal Medicine; Magee-Women's Hospital and Department of Obstetrics, Gynecology and Reproductive Sciences; School of Medicine; University of Pittsburgh; Pittsburgh PA USA
3. Department of Epidemiology; University of Pittsburgh Graduate School of Public Health; Pittsburgh PA USA
4. Department of Obstetrics, Gynecology and Reproductive Sciences and Department of Pediatrics; School of Medicine; University of Pittsburgh; Pittsburgh PA USA
5. Departments of Epidemiology and Obstetrics, Gynecology and Reproductive Sciences; University of Pittsburgh Graduate School of Public Health and School of Medicine; Pittsburgh PA USA