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, Maryland and Detroit, MI, USA,
2. Wayne State University School of Medicine, Department of Obstetrics and Gynecology, Detroit, MI, USA,
3. Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA, and
4. Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI, USA