1. Illumina Inc., San Diego, CA 92122, USA.
2. Department of Obstetrics and Gynecology and Department of Social and Preventive Medicine, Faculty of Medicine, Université Laval, Quebec City, Quebec G1V 086, Canada.
3. Department of Obstetrics and Gynecology and the Mother Infant Research Institute, Tufts University School of Medicine, Boston, MA 02111, USA.
4. Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032, USA.
5. Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX 77555, USA.