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In the UK, 8% of babies are born preterm — before 37 weeks’ gestation — which is associated with high mortality and morbidity. This study investigates how, why, for whom, and in what contexts a new national surveillance pathway is or isn’t being implemented across maternity services.
Currently, some women at risk of preterm birth are referred to a specialist Preterm Birth Prevention Clinic alongside standard care, while the majority receive standard care only. NHS England guidance (2019) recommends a new Preterm Birth Surveillance Pathway to standardise care and reduce the preterm birth rate.
About the pathway
The pathway involves midwives assessing all women for their risk of preterm birth. Women at high or intermediate risk are referred to a Preterm Birth Prevention (PBP) Clinic alongside normal care, where they can be offered further screening tests and interventions. This pathway is in the NHS standard contract — maternity providers should have implemented it by April 2020.
The IMPART study uses a realist evaluation approach to understand how, why, for whom, and in what contexts the pathway is or isn’t being implemented across maternity services in England.

Identify contexts and mechanisms leading to both positive and negative outcomes in implementing the Preterm Birth Prevention pathway
Understand the relationship between contexts, mechanisms and outcomes in implementing the pathway
Identify and assess a range of implementation outcomes, including any unintended consequences
Determine optimal implementation theories for effective national uptake of the pathway and produce a set of recommendations for implementing it across a range of hospitals
Secondary clinical objective
To determine whether implementation of the pathway will reduce the incidence of preterm birth (both liveborn and stillborn).
The research uses a realist evaluation approach — a methodology based on the assumption that programmes work under certain conditions and are influenced by how different stakeholders respond to them. Rather than simply asking ‘what works?’, realist evaluation asks ‘what works, for whom, and in what circumstances?’ (Pawson and Tilley, 1997).
Mixed methods data collection includes:
While the current preterm rate is 8% in the UK, particular groups of women are more likely to have a preterm birth — including women living in deprived neighbourhoods and women from Black, Asian and minority ethnic backgrounds.
Areas in south London include some of the most deprived parts of the city, and south London is one of the most ethnically diverse areas in England. Babies born preterm have high rates of neonatal mortality; those that survive often have short and long-term health problems that can affect their whole adult life. This research is therefore directly relevant to the communities we serve.
This research produces a set of recommendations for implementing the pathway in a range of hospitals. Effective implementation could:
A patient and public involvement (PPI) group of women who have recently given birth was established for the entirety of the project, with effort made to recruit women from groups at higher risk of preterm birth — particularly women who identify as Black or Black British.
As realist evaluation is an iterative, non-linear process, regular PPI input throughout the study was crucial to honing the research at each stage. The project advisory group met regularly to receive updates on research progress and ensure the focus remained embedded in the needs of those the research aims to benefit. At the end of the study, a dissemination plan was co-developed with the group.
The research involved collaboration with networks and experts in preterm birth, realist evaluation, implementation science and midwifery. Partner organisations include:
![]() Professor Jane Sandall CBE Theme lead; Professor of Social Science and Women’s Health, King’s College London; midwife and NIHR Senior Investigator |
SD
Dr Simon Dalkin Supervisor; realist evaluation expert, Northumbria University |
Original source: arc-sl.nihr.ac.uk — NIHR ARC South London legacy content archived June 2026.