About the Authors

Rebecca Mary Diane Smyth

rebecca.smyth@manchester.ac.uk

Affiliation School of Nursing, Midwifery and Social Work, University of Manchester, Manchester, England, United Kingdom

Elizabeth Gargon

Affiliation Department of Biostatistics, University of Liverpool, Liverpool, England, United Kingdom

Jamie Kirkham

Affiliation Department of Biostatistics, University of Liverpool, Liverpool, England, United Kingdom

Lynne Cresswell

Affiliation Department of Biostatistics, University of Liverpool, Liverpool, England, United Kingdom

Su Golder

Affiliation Centre for Reviews and Dissemination, University of York, York, England, United Kingdom

Rosalind Smyth

Affiliation Department of Women's and Children's Health, University of Liverpool, Liverpool, England, United Kingdom

Paula Williamson

Affiliation Department of Biostatistics, University of Liverpool, Liverpool, England, United Kingdom

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: PRW RLS RMS SG JJK EG. Performed the experiments: PRW RLS RMS JJK LC SG. Analyzed the data: PRW RLS RMS EG JJK LC SG. Contributed reagents/materials/analysis tools: PRW RLS RMS EG SG JJK LC . Wrote the paper: PRW RLS RMS EG JJK LC SG.