1. Department of Obstetrics and Gynecology, University of Utah Health, Salt Lake City, UT, USA
2. Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA
3. Department of Obstetrics and Gynecology, Ohio State University, Columbus, OH, USA
4. Department of Obstetrics and Gynecology, Harvard Medical School, Boston, MA, USA
5. Department of Obstetrics and Gynecology, Northwestern University, Evanston, IL, USA
6. Department of Medicine, Division of Pulmonary, Critical Care, Sleep and Occupational Medicine, Indiana University, Bloomington, IN, USA
7. Department of Obstetrics and Gynecology, School of Medicine, John Hopkins University, Baltimore, MD, USA