More research needed as programme to identify small babies in womb does not improve detection

A programme of care introduced to better detect small babies during pregnancy does not identify more small babies than existing best-practice identification methods, a study supported by Tommy’s has found.
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Most babies that are smaller than expected will be healthy, but some are at increased risk of complications before and after birth. 

Up to 40% of all stillbirths are believed to be related to poor growth.

Yet currently only around 1 in 4 of these small babies are identified in pregnancy. This means it can be hard for doctors and midwives to offer personalised care to reduce the risks of complications happening. 

A team of scientists led by King’s College London and funded by Tommy’s, Sands and Guy’s and St Thomas’ Charity evaluated how well the Growth Assessment Protocol (GAP), is in improving detection. 

Developed by the Perinatal Institute, the GAP programme includes the use of customised centile charts to measure the distance between the top of the womb and the pubic bone, and estimated weight measurements for the baby in the womb, alongside evidence-based protocols and risk assessment, new training for clinical staff, and missed-case audits and benchmarking.

It’s a complex antenatal care package which hoped to improve the detection of small babies, but results from previous evaluations have been conflicting. 

The team at King’s, with national and international partners, carried out the first randomised trial of GAP in England. Maternity hospitals across 13 NHS Trusts were allocated to either standard care or GAP. 

The rate of detection of small babies by ultrasound was measured and compared between hospitals using GAP to those which were not. The impact of using GAP on the health of mother and baby during and after birth was also evaluated.

The study revealed GAP did not improve the detection of babies who were small for their gestational age compared to normal care.

There was also no difference between maternity units using GAP and those that were not when it came to whether women had a vaginal birth or caesarean, whether birth was complicated, or whether babies needed to stay in the neonatal unit after they were born. 

Research lead Professor Dharmintra Pasupathy from King’s College London and the University of Sydney says:

“Our findings need to be interpreted in context of standard care practice in the UK, which already recommends doctors and midwives arrange additional scans and increased surveillance for women at high risk. 

“The findings suggest that the GAP does not provide additional benefit in the detection of small babies when compared to current UK recommendations, which should continue to be considered best practice.” 

Consistent with previous research into GAP’s effectiveness, there was a lot of variation in how GAP was used between maternity hospitals assigned to use it. Professor Pasupathy and the team recommend that future studies on GAP should incorporate a consistent approach to evaluate its use in clinical care.  

Kath Abrahams, Tommy’s CEO says:

“We know that babies who are small for gestational age are at greater risk of stillbirth and other complications as well as a much higher chance of a stay in NICU, yet at present only a quarter of smaller babies can be identified with our current care methods. 

“While developments such as GAP have not shown improved results compared to standard  care practice, it’s important that we encourage research to continue to explore how measuring and monitoring can be improved so every parent and baby has the best chance of a healthy pregnancy, birth and start in life.”

The study was published in the open-access journal PLOS Medicine on Tuesday 21 June 2022.