About the Authors

Robert W. Powers

powersrw@upmc.edu

Affiliation Department of Obstetrics, Gynecology and Women's Health, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America

Arun Jeyabalan

Affiliation Department of Obstetrics, Gynecology and Women's Health, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America

Rebecca G. Clifton

Affiliation The George Washington University Biostatistics Center, Washington, D.C., United States of America

Peter Van Dorsten

Affiliation Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, South Carolina, United States of America

John C. Hauth

Affiliation Department of Obstetrics and Gynecology, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States of America

Mark A. Klebanoff

Affiliation Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland, United States of America

Marshall D. Lindheimer

Affiliation Department of Obstetrics and Gynecology, University of Chicago School of Medicine, Chicago, Illinois, United States of America

Baha Sibai

Affiliation Department of Obstetrics and Gynecology, University of Tennessee School of Medicine, Memphis, Tennessee, United States of America

Mark Landon

Affiliation Department of Obstetrics and Gynecology, The Ohio State University School of Medicine, Columbus, Ohio, United States of America

Menachem Miodovnik

Affiliation Department of Obstetrics and Gynecology, University of Cincinnati School of Medicine, Cincinnati, Ohio, United States of America

for the Eunice Kennedy Shriver National Institute of Child Health Human Development Maternal-Fetal Medicine Units Network

Membership of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network is provided in the Acknowledgments.

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: RP. Performed the experiments: RP AJ. Analyzed the data: RP RGC. Wrote the paper: RP AJ RGC PVD JCH MK ML BS ML MM.