The POOL study is a large UK based cohort study exploring the safety of waterbirth for mothers and babies.  Although the use of water immersion during labour for pain relief is a popular choice and offered in most UK maternity units, clinical questions remain as to whether giving birth in water is as safe as leaving the water prior to birth. As the clinical outcomes of interest are uncommon a large study was required. To answer all study objectives, the POOL study plans to use records relating to over 800,000 births that occurred between January 2015 and June 2022.

Midwives enter many data items relating to pregnancy and births into local electronic maternity information systems.  The study was the first to adapt existing NHS clinical maternity information systems at participating NHS sites to collect additional data specifically for research purposes. By adding additional fields into maternity information systems, the study was able to maximise the use of existing collected data, whilst efficiently collecting study specific data items.

A team of researchers including Chief Investigator Professor Julia Sanders and Research Fellow Fiona Lugg-Widger, from Cardiff University collaborated with Wellbeing Software®, a heath technology company to adapt the Euroking maternity information system at 26 participating NHS sites in England and Wales.

For any baby requiring additional care following birth, in the study data from the maternity information systems is matched to that held to that held by the UK National Neonatal Research Database which holds identifiable, individual level clinical data on all babies admitted to a neonatal unit in England, Wales or Scotland.

Professor Julia Sanders said ‘The POOL study is long overdue, but because of its required scale and complexity it has been many years in development and delivery. The novel methods used in the POOL study, of adapting clinical information systems for the collecting of research data, have real potential, but the governance and practical obstacles of using routine NHS data in this way remain significant.’

Their research article, ‘The feasibility of adapting UK maternity clinical information systems for observational research: recent experiences of the POOL study’ published in the International Journal of Population Data Science (IJPDS), describes how the team collected the additional data including methods of extraction from sites. The article also shares the process of cleaning the data, with particular emphasis on the importance of a pilot to test methods of data transfer and linkage. The paper also reports and explores the anticipated, as well as unexpected, challenges of collecting routine data on this scale.

Click here to read the full open access article


The POOL study Chief Investigator, Professor Julia Sanders

Lugg-Widger, F., Barlow, C., Cannings-John, R., Gale, C., Houlding, N., Milton, R., Plachcinski, R., Robling, M. and Sanders, J. (2023) “The practicalities of adapting UK maternity clinical information systems for observational research: Experiences of the POOL study”, International Journal of Population Data Science, 8(1). Available at: (Accessed: 7 August 2023).