About the Authors

Hannah E. Knight

hknight@rcog.org.uk

Affiliations Nuffield Department of Obstetrics & Gynaecology, University of Oxford, Oxford, United Kingdom, Oxford Maternal & Perinatal Health Institute, University of Oxford, Oxford, United Kingdom

Alice Self

Affiliations Nuffield Department of Obstetrics & Gynaecology, University of Oxford, Oxford, United Kingdom, Oxford Maternal & Perinatal Health Institute, University of Oxford, Oxford, United Kingdom, Sandwell General Hospital, Lyndon, West Bromwich, United Kingdom

Stephen H. Kennedy

Affiliations Nuffield Department of Obstetrics & Gynaecology, University of Oxford, Oxford, United Kingdom, Oxford Maternal & Perinatal Health Institute, University of Oxford, Oxford, United Kingdom

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: HK SK. Performed the experiments: HK AS. Analyzed the data: HK AS. Wrote the paper: HK AS SK.