About the Authors

Cande V. Ananth

cande.ananth@columbia.edu

Affiliations Department of Obstetrics and Gynecology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America, Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, United States of America

Katherine M. Keyes

Affiliation Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, United States of America

Ava Hamilton

Affiliation Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, United States of America

Mika Gissler

Affiliation THL National Institute for Health and Welfare, Helsinki, Finland and NHV Nordic School of Public Health, Gothenburg, Sweden

Chunsen Wu

Affiliation Section for Epidemiology, Department of Public Health, Aarhus University, Aarhus, Denmark

Shiliang Liu

Affiliation Health Surveillance and Epidemiology Division, Centre for Chronic Disease Prevention, Public Health Agency of Canada, Ottawa, Canada

Miguel Angel Luque-Fernandez

Affiliation Department of Epidemiology, School of Public Health, Harvard University, Boston, Massachusetts, United States of America

Rolv Skjærven

Affiliations Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway, Medical Birth Registry of Norway, Norwegian Institute of Public Health, Bergen, Norway

Michelle A. Williams

Affiliation Department of Epidemiology, School of Public Health, Harvard University, Boston, Massachusetts, United States of America

Minna Tikkanen

Affiliation Department of Obstetrics and Gynecology, University Central Hospital, Helsinki, Finland

Sven Cnattingius

Affiliation Clinical Epidemiology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: CVA. Analyzed the data: AH KMK CVA. Wrote the paper: CVA KMK AH MG CW SL MALF RSS MAW MT SC.