PO03 Effect of INTERGROWTH-21st charts on stillbirths rates in England: retrospective cohort study
Pregnancy Outcome
Information
OBJECTIVE Prevention of stillbirths relies on antenatal identification of babies at-risk due to growth restriction. Fetal growth charts vary in antenatal screen positive rates for small for gestational age (SGA). We investigated the effect the introduction of INTERGROWTH 21st charts had on stillbirth rates.
METHODS The 8 NHS Trusts in North East North Cumbria (NENC) moved simultaneously from GROW to INTERGROWTH fetal weight charts in April 2024. Annual stillbirth rates for 2023 and 2024 were obtained from ONS1,2. We also compared as control group the stillbirth rates with 8 pre-selected, birth rate-matched English Trusts that had continued with GROW charts over the same time period.
RESULTS The average SGA screen positive rate in NENC dropped by 49%, from 9.7% to 4.9% with the change from GROW to INTERGROWTH charts. Stillbirth rates (per 1000) in this network increased from 3.15 in 2023 to 4.16 in 2024 (p<0.05), representing a 31.9% increase. In the matched control group, the stillbirth rate reduced slightly from 3.36 to 3.09 (-8.1%; p=0.46), similar to the slight decline in England (see Figure). The NENC’s stillbirth rate (3.15) was similar to that of the matched hospitals (3.36) in 2023 (-6.3%, p=0.65) but rose in 2024 to 4.16, 34.5% higher than that in the matched control (3.09; p<0.05).
CONCLUSIONS INTERGROWTH fetal weight charts miss babies at risk of fetal growth restriction. This is likely due to a near-halving of SGA screen positive rates by IG21 compared to GROW3 and consistent with previous prediction based on NHS data4.
METHODS The 8 NHS Trusts in North East North Cumbria (NENC) moved simultaneously from GROW to INTERGROWTH fetal weight charts in April 2024. Annual stillbirth rates for 2023 and 2024 were obtained from ONS1,2. We also compared as control group the stillbirth rates with 8 pre-selected, birth rate-matched English Trusts that had continued with GROW charts over the same time period.
RESULTS The average SGA screen positive rate in NENC dropped by 49%, from 9.7% to 4.9% with the change from GROW to INTERGROWTH charts. Stillbirth rates (per 1000) in this network increased from 3.15 in 2023 to 4.16 in 2024 (p<0.05), representing a 31.9% increase. In the matched control group, the stillbirth rate reduced slightly from 3.36 to 3.09 (-8.1%; p=0.46), similar to the slight decline in England (see Figure). The NENC’s stillbirth rate (3.15) was similar to that of the matched hospitals (3.36) in 2023 (-6.3%, p=0.65) but rose in 2024 to 4.16, 34.5% higher than that in the matched control (3.09; p<0.05).
CONCLUSIONS INTERGROWTH fetal weight charts miss babies at risk of fetal growth restriction. This is likely due to a near-halving of SGA screen positive rates by IG21 compared to GROW3 and consistent with previous prediction based on NHS data4.
Poster Day
Friday 27th March