1. Department of Obstetrics and Gynecology, Faculty of Medicine , Universidad de los Andes , Las Condes, Santiago , Chile
2. Department of Public Health and Epidemiology, Faculty of Medicine , Universidad de los Andes , Santiago , Chile
3. Center for Research and Innovation in Maternal-Fetal Medicine (CIMAF) , Hospital Sótero del Río , Santiago , Chile
4. Division of Obstetrics and Gynecology, School of Medicine , Pontificia Universidad Católica de Chile , Santiago , Chile
5. Perinatology Research Branch, NICHD/NIH/DHHS , Bethesda, MD and Detroit, MI , USA
6. Department of Obstetrics and Gynecology , Clínica Dávila , Santiago , Chile
7. Department of Obstetrics and Gynecology , University of Michigan , Ann Arbor, MI , USA
8. Department of Epidemiology and Biostatistics , Michigan State University , East Lansing, MI , USA
9. Center for Molecular Medicine and Genetics , Wayne State University , Detroit, MI , USA