CRediT contribution statement
Julia Sanders (https://orcid.org/0000-0001-5712-9989): Conceptualisation, Funding acquisition, Methodology, Investigation, Project administration, Supervision, Visualisation, Writing – original draft, Writing – reviewing and editing.
Christian Barlow (https://orcid.org/0000-0001-5759-0310): Data curation, Methodology, Investigation, Project administration, Visualisation, Writing – original draft, Writing – reviewing and editing.
Peter Brocklehurst (https://orcid.org/0000-0002-9950-6751): Conceptualisation, Funding acquisition, Methodology, Project administration, Writing – reviewing and editing, Data interpretation.
Rebecca Cannings-John (https://orcid.org/0000-0001-5235-6517): Conceptualisation, Funding acquisition, Methodology, Investigation, Project administration, Data curation, Formal analysis, Visualisation, Writing – original draft, Writing – reviewing and editing, Data interpretation.
Susan Channon (https://orcid.org/0000-0002-5394-1483): Conceptualisation, Funding acquisition, Methodology, Investigation, Project administration, Writing – reviewing and editing, Data interpretation, Data collection.
Christopher Gale (https://orcid.org/0000-0003-0707-876X): Conceptualisation, Funding acquisition, Methodology, Investigation, Project administration, Writing – original draft, Writing – reviewing and editing.
Judith Cutter (https://orcid.org/0000-0003-2279-4801): Project administration, Writing – reviewing and editing, Data interpretation.
Jacqueline Hughes (https://orcid.org/0000-0002-9498-8376): Investigation, Writing – original draft, Writing – reviewing and editing.
Billie Hunter (https://orcid.org/0000-0002-8064-3609): Conceptualisation, Funding acquisition, Methodology, Project administration, Writing – reviewing and editing.
Fiona Lugg-Widger (https://orcid.org/0000-0003-0029-9703): Conceptualisation, Funding acquisition, Methodology, Project administration, Writing – original draft, Writing – reviewing and editing.
Sarah Milosevic (https://orcid.org/0000-0003-1973-8286): Methodology, Investigation, Project administration, Writing – original draft, Writing – reviewing and editing.
Rebecca Milton (https://orcid.org/0000-0001-5985-3866): Project administration, Writing – original draft, Writing – reviewing and editing, Data collection.
Leah Morantz (https://orcid.org/0000-0003-1786-4836): Conceptualisation, Funding acquisition, Project administration, Writing – reviewing and editing.
Mary Nolan: Conceptualisation, Funding acquisition, Methodology, Project administration.
Rachel Plachcinski (https://orcid.org/0000-0001-9908-0773): Conceptualisation, Funding acquisition, Project administration, Writing – reviewing and editing.
Shantini Paranjothy (https://orcid.org/0000-0002-0528-3121): Conceptualisation, Funding acquisition, Writing – reviewing and editing.
Michael Robling (https://orcid.org/0000-0002-1004-036X): Conceptualisation, Funding acquisition, Project administration, Writing – reviewing and editing, Data interpretation.
Acknowledgements
We thank all mothers whose data are included in the study. You have generated new knowledge of importance to parents who follow you. The study includes data relating to babies who died, and mothers and babies who were harmed during birth. We recognise and remember your loss and sadness.
Study Steering Committee
We would like to acknowledge and thank the Study Steering Committee [Catherine Williams, Chairperson (from February 2020); Dr Annette Briley, Chairperson (April 2018–February 2020); Professor Ben Stenson, Dr Virginia Chiocchia, Professor Christine McCourt and Professor Derek Tuffnell for their continued support]. We would also like to acknowledge Abigail Holmes (previous Cardiff PI) and Mervi Jokinen for their contributions to the POOL Study.
Study sites
Our thanks go to all staff at all 26 NHS study sites for their continued support and contributions to the POOL Study, particularly the midwives who entered vast amounts of data relating to pregnancies and births.
University Hospital of Wales, Cardiff and Vale University Health Board: Judith Cutter (PI), Consultant Midwife for Public Health and Vulnerable Families.
Salisbury District Hospital, Salisbury NHS Foundation Trust: Abby Rand (PI), Research Midwife; and Holly Morgan, Clinical Trials Assistant.
Queen’s Hospital, Barking, Havering and Redbridge University Hospitals: Annemarie McGregor (PI).
Blackpool Victoria Hospital, Blackpool Teaching Hospitals NHS Foundation Trust: Eric Mutema (PI), Consultant Obstetrician and Gynaecologist; Alanna Beasley, Research Nurse; Sarah Traynor, Research Midwife; Vicki Cunliffe, Research Healthcare Assistant; and Shamina Hankinson, Research Administrator.
Royal Bolton Hospital, Bolton NHS Foundation Trust: Emma Tanton (PI), Clinical Research Midwife.
Darent Valley Hospital, Dartford and Gravesham NHS Trust: Suzanne Curwood (PI), Lead Midwife Birth Centre; Tracy Edmunds, Clinical Trials Practitioner; and Paul Seymour, Clinical Systems Manager (Maternity).
William Harvey Hospital and Queen Elizabeth the Queen Mother Hospital East Kent Hospitals University NHS Foundation Trust: Sal Higgins (PI), Joanne Deery, Research Nurse; Tracy Halzleton and James Rand, Clinical Research Practitioners. Reanne Solly, Clinical Trials Administrator/Clinical Research Practitioner. Sharon Turney, Gabriella Tutt, Vicki Priestley, Liam Austin and Emma Ingall, Clinical Trials Administrators.
Frimley Park Hospital, Frimley Health NHS Foundation Trust: Emma Luhr, Danielle Eghobamien, Rebecca Edwards, Priscilla Dike (PI), Tracy Andrew, Lianne Chapman, Clare Denford and Sarah Marshall.
Hillingdon Hospital, The Hillingdon Hospitals NHS Foundation Trust: Nicky Wilkins (PI), Consultant Midwife; Geraldine Landers, R&D Manager; and Nerea Rodal Prieto, Research Midwife.
St Mary’s Hospital, Isle of Wight NHS Trust: Dr Elinor Jenkins (PI), Ward Manager, Maternity.
West Suffolk Hospital, West Suffolk NHS Foundation Trust: Helen Cockerill, Research Nurse (Paediatrics); Paul Oats, R&D Manager; Barkha Sinha (PI), Consultant, Department of Obstetrics and Gynaecology.
James Paget University Hospital, James Paget University Hospitals NHS Foundation Trust: Katy Dogbey (PI), Consultant Midwife; and Sarah Girling, Research Management Co-ordinator.
Leicester Royal Infirmary, University Hospitals of Leicester: Julia Austin, Consultant Midwife; Molly Patterson (PI), Women’s Research Manager; Gina Mulheron, Sharon Bates, Claire Dodd, Patricia Amos, Beverley Cowlishaw and Sharon Raper, Research Midwives; Magdalena Kierzenkowska, Research Development Midwife; Rupa Modi and Mamta Joshi, Research Support Officers.
Tunbridge Wells Hospital and Maidstone Hospital, Maidstone and Tunbridge Wells NHS Trust: Louise Swaminathan (PI), Senior Research Midwife; Lydia Ufton, Clinical Research Midwife; and Susan Powley, IT Matron.
North Manchester General Hospital and Wythenshawe Hospital, Manchester University NHS Foundation Trust: Dr Ghazia Saleemi (PI), Consultant Obstetrician; Sarah Thomas and Megan Laws, Research Midwives; and Andy Fairclough, Clinical Trials Manager.
Medway Maritime Hospital, Medway NHS Foundation Trust: Sarah-Jayne Ambler (PI), Clinical Research Manager in Midwifery; and Rachael Gardner, Fetal Medicine Research Midwife.
Royal Victoria Infirmary, The Newcastle upon Tyne Hospitals NHS Foundation Trust: Dr Therese Hannon (PI), Consultant in Obstetrics and Fetal Medicine; Fiona Yelnoorkar, Lead Midwife, CRN NENC and Matron, Directorate of Clinical Research; Victoria Murtha, Senior Research Nurse and Team Lead; Andrea Fenn, Lead Research Midwife; Marc Davies, Research Project Manager; Joseph Taylor, Research Information Officer; Chris Saunders, Senior Midwife, The Newcastle Birthing Centre.
Southmead Hospital, North Bristol NHS Trust: Nichola Bale (PI), Senior Research Midwife; Mary Alvarez, Senior Research Midwife; Sally Hall, Research Administrator; Michelle Mayer, Digital Midwife and Women and Children’s Research Team.
North Tyneside Hospital, Northumbria Healthcare NHS Foundation Trust: Dr Vinita Raheja (PI), Consultant Obstetrician and Gynaecologist; and Jessica Reynolds, IR&D study Co-ordinator.
The Royal Oldham Hospital, The Pennine Acute Hospitals NHS Trust, Northern Care Alliance NHS Group: Chloe Rishton (PI), Research Nurse; Rachel Newport and Zainab Sarwar, Research Midwives; and Grainne O’Connor, Research Nurse.
Royal Cornwall Hospital, Royal Cornwall Hospitals NHS Trust: Ruth Bowen (PI) and Katherine Lane, Research Midwives, and the Maternity IT team.
The James Cook University Hospital, South Tees Hospitals NHS Foundation Trust: Hazel Alexander (PI), Research Midwife/Sonographer.
Stepping Hill Hospital, Stockport NHS Foundation Trust: Wiesia Woodyatt (PI), Daisy Tudor, Research Midwife; Susan Hopkins, Clinical Trials Assistant; and Claire Bradbury, Digital Midwife.
Royal Albert Edward Infirmary, Wrightington, Wigan and Leigh Teaching Hospitals NHS Foundation Trust: Amit Verma (PI), Consultant Gynaecologist and Obstetrician; Diane Heaton and Christopher Moore R&D Co-ordinators; Anne Isherwood, Research Midwife/Nurse; Rebecca Smith, Research Assistant; and Isabelle Sykes, R&D Assistant.
St George’s Hospital, St George’s University Hospitals NHS Foundation Trust: Emily Marler (PI), Senior Research Midwife; and Temitope Bankole, Research Project Manager.
Norfolk and Norwich University Hospital, Norfolk and Norwich University Hospitals NHS Foundation Trust: Laura Harris (PI), Research Midwife.
Patient data statement
This work uses data provided by patients and collected by the NHS as part of their care and support. Using patient data is vital to improve health and care for everyone. There is huge potential to make better use of information from people’s patient records, to understand more about disease, develop new treatments, monitor safety, and plan NHS services. Patient data should be kept safe and secure, to protect everyone’s privacy, and it is important that there are safeguards to make sure that they are stored and used responsibly. Everyone should be able to find out about how patient data are used. #datasaveslives You can find out more about the background to this citation here: https://understandingpatientdata.org.uk/data-citation
Data-sharing statement
Applicants interested in requesting data for non-commercial purposes should apply via the data application form available on the Centre for Trials Research website (www.cardiff.ac.uk/centre-for-trials-research/collaborate-with-us/data-requests). Following an internal and peer review of the application and subject to approval, data may be released under a data transfer agreement. In the first instance, enquiries about access to the data should be addressed to Professor Julia Sanders, School of Healthcare Sciences, Cardiff University.
Ethics statement
The protocol was approved by NHS Wales Research Ethics Committee on 18 September 2018 (18/WA/0291) and the transfer of identifiable data was approved by HRA CAG on 2 November 2018 (18CAG0153).
Information governance statement
Cardiff University and the Centre for Trials Research are committed to handling all personal information in line with the UK Data Protection Act (2018) and the General Data Protection Regulation (EU GDPR) 2016/679. Under the Data Protection legislation, Cardiff University is the Data Controller, and you can find out more about how we handle personal data, including how to exercise your individual rights and the contact details for our Data Protection Officer here: www.cardiff.ac.uk/public-information/policies-and-procedures/data-protection.
Data storage
All POOL Study data are held on the Research Data Storage (RDS) space on Cardiff University; the data will remain on the RDS Space until it is destroyed at the end of the archive retention period. The space cannot be accessed without express permission and data will be archived in accordance with CTR and Cardiff University processes.
Disclosure of interests
Full disclosure of interests: Completed ICMJE forms for all authors, including all related interests, are available in the toolkit on the NIHR Journals Library report publication page at https://doi.org/10.3310/GGHD6684
Primary conflicts of interest: All authors have completed the ICMJE uniform disclosure form and declare: the NIHR provided funding to the employing institutions of Julia Sanders, Christian Barlow, Peter Brocklehurst, Rebecca Cannings-John, Susan Channon, Judith Cutter, Billie Hunter, Fiona Lugg-Widger, Sarah Milosevic, Shantini Paranjothy and Michael Robling to support the undertaking of the submitted work.
Peter Brocklehurst was member of CTUs funded by NIHR committee, HTA MNCH panel 1 from December 2014 to 30 June 2018. Rebecca Cannings-John was HTA associate board member. Christopher Gale received salary support from the Medical Research Council paid to his institution through a Personal Fellowship (Clinician Scientist and Transition Support); there are no financial relationships with any organisations that might have an interest in the submitted work in the previous 3 years; there are no other relationships or activities that could appear to have influenced the submitted work.
The Centre for Trials Research receives funding from Health and Care Research Wales and Cancer Research UK.
Disclaimer
Every effort has been made to obtain the necessary permissions for reproduction, to credit original sources appropriately and to respect copyright requirements. However, despite our diligence, we acknowledge the possibility of unintentional omissions or errors and we welcome notifications of any concerns regarding copyright or permissions.
Publications
Milosevic S, Channon S, Hunter B, Nolan M, Hughes J, Barlow C, et al. Factors influencing the use of birth pools in the United Kingdom: perspectives of women, midwives and medical staff. Midwifery 2019:79:102554. https://doi.org/10.1016/j.midw.2019.102554
Milosevic S, Channon S, Hughes J, Hunter B, Nolan M, Milton R, Sanders J. Factors influencing water immersion during labour: qualitative case studies of six maternity units in the United Kingdom. BMC Pregnancy Childb 2020:20:719. https://doi.org/10.1186/s12884-020-03416-7
Milton R, Sanders J, Barlow C, Brocklehurst P, Cannings-John R, Channon S, et al.. Establishing the safety of waterbirth for mothers and babies: a cohort study with nested qualitative component: the protocol for the POOL Study. BMJ Open 2021;11:e040684. https://doi.org/10.1136/bmjopen-2020-040684
Lugg-Widger F, Barlow C, Cannings-John R, Gale C, Houlding N, Milton R, et al. The practicalities of adapting UK maternity clinical information systems for observational research: experiences of the POOL Study. Int J Popul Data Sci 2023;8. https://doi.org/10.23889/ijpds.v8i1.2072
Sanders J, Barlow C, Brockhurst P, Cannings-John, R, Channon, S, Cutter J, et al. Maternal and neonatal outcomes among spontaneous vaginal births occurring in or out of water following intrapartum water immersion: The POOL cohort study. BJOG 2024;131:1650-9. https://doi.org/10.1111/1471-0528.17878
Sanders J, Barlow C, Brockhurst P, Cannings-John, R, Channon, S, Cutter J, et al. Characteristics of women, intrapartum interventions, and maternal and neonatal outcomes among users of intrapartum water immersion: The UK POOL Cohort Study. Birth 2025. https://doi.org/10.1111/birt.12921
Disclaimers
This article presents independent research funded by the National Institute for Health and Care Research (NIHR). The views and opinions expressed by authors in this publication are those of the authors and do not necessarily reflect those of the NHS, the NIHR, the HTA programme or the Department of Health and Social Care. If there are verbatim quotations included in this publication the views and opinions expressed by the interviewees are those of the interviewees and do not necessarily reflect those of the authors, those of the NHS, the NIHR, the HTA programme or the Department of Health and Social Care.