Preventing cerebral palsy in premature babies: the PReCePT programme

What we did

We compared magnesium sulfate use in maternity units for the year before and the year after they implemented PReCePT, to measure the impact of the national programme. We also compared its use in maternity units in 2018-22, with its use in 2017.

We accounted for factors such as:

• The baby’s birth weight and how long the pregnancy lasted
• Whether it was a multiple birth (twins and triplets)
• The mother’s age, ethnicity and level of poverty
• Any relevant complications of the pregnancy
• The type of maternity unit, for example a high dependency unit or a neonatal intensive care unit
• How the use of magnesium sulfate would have likely increased over time, without the PReCePT programme

We analysed data from the UK National Neonatal Research Database. This is a reliable database with high-quality information from neonatal units across the UK.

We used this data to see if magnesium sulfate use had increased after PReCePT was introduced, and to estimate whether the programme was both effective and cost-effective.

We also investigated whether the COVID-19 pandemic affected use of magnesium sulfate.

Finally, we also looked at how magnesium sulfate was being used in Scotland and Wales, to see if what had been happening there was similar or different to what had been happening in England.

What we found and what this means

Analysis after a year of PReCePT

While use of magnesium sulfate had been increasing before, our research showed that PReCePT was able to accelerate uptake. It increased by 6.3 percentage points on average across all maternity units in England during the first year, over and above the increase that would be expected over time as the practice spread organically. After also adjusting for variations in when maternity units started the programme, the increase in use of magnesium sulfate was 9.5 percentage points. By May 2020, on average 86.4% of eligible mothers were receiving magnesium sulfate.

We also estimated that the programme’s first year could be associated with a lifetime saving to society of £3 million. This accounts for the costs of the programme, administering the treatment and of cerebral palsy to society over a lifetime, and the associated health gains of avoiding cases. This is across all the extra babies the programme helped get access to the treatment during the first year.

Analysis of four years of PReCePT

We also found that in England, magnesium sulfate use improved from about 66% in 2017 (the year before PReCePT) to about 86% in 2022 (four years after PReCePT).

After accounting for other things that might have changed over time, we estimated that PReCePT itself was responsible for about 6 percentage points (or about a third) of this total 20 percentage points improvement. The statistical analysis showed that the real amount of improvement due to PReCePT is likely to be between about 3 and 9 percentage points.

We balanced the costs of running the programme and giving magnesium sulphate against the cost-savings from preventing cerebral palsy in all the babies who had been treated. From this, we estimated that the national PReCePT programme had a ‘net monetary benefit’ of £597,000, meaning it saved more money than it costed.

The impact of the pandemic

Since the COVID-19 pandemic in 2020, it looks like magnesium sulphate use might have declined slightly. Use of antenatal steroids, another protective treatment for preterm babies, also appears to have declined the same amount since the pandemic.

The pandemic, which had a negative effect on many aspects of healthcare, could have had a similar negative effect on maternity care. This trend is concerning.

Comparing with Scotland and Wales

Comparing England with Scotland and Wales, by 2022 all three nations were at similar levels, with around 80-85% of eligible mothers being treated. However, it also seemed the PReCePT programme accelerated magnesium sulfate use in England faster than in Scotland and Wales.

What next?

There are two important studies to do next.

One is to check equity in treatment. We know that overall more mothers are being treated, but it’s important to check if all mothers have benefitted equally, or if there are any groups that we might need to work harder to treat.

The other study is to check that these improvements in treatment really have, as expected, resulted in fewer children having cerebral palsy.

We also hope to develop a prototype toolkit to support implementation of new interventions in NICE guidance. This is a vital step in helping NHS hospitals put research evidence and national clinical guidelines into practice.