About the Authors

Olaa Mohamed-Ahmed

olaa.mohamed-ahmed@npeu.ox.ac.uk

Affiliation National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, United Kingdom

Cathy Nelson-Piercy

Affiliations Division of Women’s Health, King’s College London, Women’s Health Academic Centre, King’s Health Partners, United Kingdom, Obstetric Medicine, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom

Kate Bramham

Affiliation Division of Women’s Health, King’s College London, Women’s Health Academic Centre, King’s Health Partners, United Kingdom

Haiyan Gao

Affiliation National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, United Kingdom

Jennifer J. Kurinczuk

Affiliation National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, United Kingdom

Peter Brocklehurst

Affiliation Institute for Women’s Health, University College London, United Kingdom

Marian Knight

Affiliation National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, United Kingdom

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: CNP JJK PB MK. Analyzed the data: OMA. Wrote the paper: OMA. Contributed to writing the manuscript: CNP KB HG JJK PB MK. Contributed to the analysis: JJK MK HG.