About the Authors

Kathryn E. Fitzpatrick

Affiliation National Perinatal Epidemiology Unit, University of Oxford, Oxford, United Kingdom

Jennifer J. Kurinczuk

Affiliation National Perinatal Epidemiology Unit, University of Oxford, Oxford, United Kingdom

Zarko Alfirevic

Affiliation Division of Perinatal and Reproductive Medicine, University of Liverpool, Liverpool Women's Hospital, Liverpool, United Kingdom

Patsy Spark

Affiliation National Perinatal Epidemiology Unit, University of Oxford, Oxford, United Kingdom

Peter Brocklehurst

Affiliation National Perinatal Epidemiology Unit, University of Oxford, Oxford, United Kingdom

Marian Knight

marian.knight@npeu.ox.ac.uk

Affiliation National Perinatal Epidemiology Unit, University of Oxford, Oxford, United Kingdom

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: JJK ZA PS PB MK. Performed the experiments: MK. Analyzed the data: KF JJK ZA PS PB MK. Wrote the first draft of the manuscript: KF MK. Contributed to the writing of the manuscript: JJK ZA PS PB. ICMJE criteria for authorship read and met: KF JJK ZA PS PB MK. Agree with manuscript results and conclusions: KF JJK ZA PS PB MK.