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Case study: Widely adopted pre-eclampsia test has additional environmental benefits

Update Autumn 2023 – this work was cited by the Health Foundation in a ‘long read’ report on measures to achieve net zero in the NHS. Read the report here.


Routine use of a blood test to rule out pre-eclampsia which is keeping thousands of pregnant women safe and out of hospital, as well as reducing NHS costs, has carbon reduction benefits too. A report from the Oxford AHSN and Sustainable Healthcare Coalition assessed the additional environmental impact of all England’s maternity units adopting the placental growth factor (PlGF) test. The consequent cut in patient journeys and overnight hospital stays could potentially save over 1,000 tonnes CO2e – equivalent to three million miles of car travel each year.

What’s the challenge and solution?

Quick, accurate blood tests which can help rule out pre-eclampsia are contributing to safer pregnancies and better outcomes for tens of thousands of pregnant women and their unborn babies. More accurate diagnosis reduces the need for admission and enables a clearer focus on women needing closer monitoring. The pandemic has underlined the importance of safe and effective care, and minimising unnecessary hospital admissions. Within four years of the first real world evaluation in the Oxford AHSN region, 119 of England’s maternity units (two-thirds of the total) have adopted the test into standard clinical practice following a rapid adoption project led by AHSNs. This is a successful example of AHSNs understanding the challenges to adopting new technology and helping the NHS and innovators work together to overcome them.

As a result, the cost and clinical resource benefits of adopting PlGF testing into properly designed maternity care pathways are well established. Many of these benefits bring additional environmental benefits related to reductions in travel, hospital stays and healthcare but these had not yet been quantified.

What did we do?

Analysis was carried out to better understand the environmental impact associated with maternity service delivery incorporating PlGF-based testing for diagnosis of pre-eclampsia compared to the traditional pathway model.


Based on NICE guidance DG23 Resource Impact Model the number of projected admissions for suspected pre-eclampsia at Oxford University Hospitals fell from 920 to 536 following the introduction of PlGF testing – 386 fewer admissions per year. For each patient avoiding hospital due to the test the greenhouse gas emissions saved are 91kg CO2eq, equating to 35 tonnes across the trust as whole. In addition, 37 cubic metres less water would be used and almost two tonnes less waste generated.

Extrapolated nationwide, 1,149 tonnes CO2eq – equivalent to three million car miles – would be avoided. Annual cost savings for NHS England due to reduced admissions and patient monitoring would be £4 million (based on £250-600 saving for each woman not required to come to hospital after the test ruled out pre-eclampsia). Contributory factors include reductions in outpatient appointments, hospital admissions, pre-term births and neonatal care.

Contact: Amelia James, Environmental Sustainability Lead, Health Innovation Oxford and Kent Surrey Sussex