1. Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, MI, USA;
2. Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, USA;
3. Department of Obstetrics and Gynecology, Block E East Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin New Territories, Hong Kong;
4. Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA;
5. Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI, USA;
6. Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, USA