IJPDS International Journal of Population Data Science IJPDS 2399-4908 Swansea University 10.23889/ijpds.v10i3.3132 10:3:112 Antenatal Exposure to Ambient Fine Particulate Matter Pollution and Amoxicillin Dispensing in Infants: National Birth Cohort Study in Scotland Cannings-John Rebecca 1 Sanders Julia 1 Barlow Christy 1 Brocklehurst Peter 2 Channon Sue 1 Cutter Judith 3 Hunter Billie 1 Jokinen Mervi 4 Lugg-Widger Fiona 1 Milosevic Sarah 1 Gale Chris 5 6 Milton Rebecca 1 Morantz Leah 7 Paranjothy Shantini 8 Robling Michael 1 Plachcinski Rachel 9 Cardiff University, Cardiff, United Kingdom Birmingham Clinical Trials Unit, Birmingham, United Kingdom Cardiff and Vale University Health Board, Cardiff, United Kingdom Royal College of Midwives, London, United Kingdom Imperial College London, London, United Kingdom Chelsea and Westminster NHS Foundation Trust, London, United Kingdom Public and Patient Representative, Cardiff, United Kingdom University of Aberdeen, Aberdeen, United Kingdom Patient and Public involvement Representative, Cardiff, United Kingdom 01 06 2025 2025 8 4 3132 This work is licenced under a Creative Commons Attribution 4.0 International License. This article is available from the IJPDS website at: https://ijpds.org/article/view/3132 Objectives

The POOL study was commissioned to evaluate the safety of waterbirth in the UK using routine maternity and neonatal clinical data. We will describe the design, set-up and pilot for this data linkage study, as well as sharing challenges and successes from the process, and headline results.

 Methods

This study used the novel method of amending an existing clinical maternity database (Euroking® Maternity Information System) for the purpose of collecting additional research data fields. In combination with the extraction of existing data fields, this maximised the potential use of existing routinely collected clinical data for research purposes, whilst reducing NHS staff data collection burden. Extracted data from UK NHS sites were transferred for matching with the National Neonatal Research Database (NNRD) to ascertain outcomes for babies. Non-inferiority regression analysis was used to establish whether waterbirth was as safe for mothers and babies as leaving the water before birth.

 Results

A total of 869,744 birth records were received from 26 NHS sites in England and Wales, between January 2015 and June 2022. For the pilot, 24,000 records were extracted from one site. Data completeness for maternal and neonatal primary outcomes were acceptable. Neonatal identifiers flowed to the NNRD for successful matching, resulting in neonatal records for 6.5% of pool users. Rates of the maternal outcomes (obstetric anal sphincter injury) and the composite adverse outcome among babies were no higher among waterbirths compared with births out of water (Nulliparous women: waterbirth 4.8% vs births out of water 5.3%; adjusted odds ratio 0.97, one-sided 95% confidence interval −∞ to 1.08); Parous women: 1.1% vs 1.7%; 0.64, −∞ to 0.78; Neonates: 2.7% vs 4.4%; 0.65, −∞ to 0.79).

 Conclusion

Amending existing NHS information systems and accessing data at scale is possible, but is time consuming and technically challenging. Among women using water immersion during labour, remaining in the pool and birthing in water was not associated with an increase in the incidence of adverse primary maternal or neonatal outcomes.