1. Department of Mathematics & Statistics, Amherst College, Amherst, MA, USA
2. Department of Obstetrics and Gynecology, Beth Israel Deaconess Medical Center, Boston, MA, USA
3. Department of Obstetrics, Gynecology and Reproductive Biology, Harvard Medical School, Boston, MA, USA
4. Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
5. Department of Epidemiology and Biostatistics, Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA
6. Department of Obstetrics and Gynecology, Brigham and Women’s Hospital, Boston, MA, USA
7. Department of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst, MA, USA
8. Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA
9. Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University College of Human Medicine, Grand Rapids, MI, USA