1. Perinatology Research Branch; Program for Perinatal Research and Obstetrics; Division of Intramural Research; Eunice Kennedy Shriver National Institute of Child Health and Human Development; NIH; Bethesda MD USA
2. Perinatology Research Branch; Program for Perinatal Research and Obstetrics; Division of Intramural Research; Eunice Kennedy Shriver National Institute of Child Health and Human Development; NIH; Detroit MI USA
3. Department of Obstetrics and Gynecology; University of Michigan; Ann Arbor MI USA
4. Department of Epidemiology and Biostatistics; Michigan State University; East Lansing MI USA
5. Department of Obstetrics and Gynecology; Wayne State University School of Medicine; Detroit MI USA
6. Integrata Verona; Ostetricia Ginecologia; Azienda Ospedaliera Universitaria; Verona Italy
7. Department of Obstetrics and Gynecology; Seoul National University College of Medicine; Seoul Korea
8. Department of Pathology; University of Ulsan College of Medicine; Asan Medical Center; Seoul Korea