Accuracy and clinical effectiveness of fetal growth monitoring strategies for the prediction of small for gestational age at birth: a systematic review and meta-analysis.

Background: Smallness for gestational age has been associated with an increased risk of neonatal/fetal adverse outcomes. The Healthcare Safety Investigation Branch has issued a safety recommendation aimed at improving fetal growth monitoring strategies and reducing risk for babies. Objectives: The objective was to summarise available evidence to inform the Healthcare Safety Investigation Branch recommendation. The review comprised four research questions on: effects of fetal growth monitoring on neonatal/parental outcomes; effects of implementing fetal growth monitoring guidelines on neonatal/parental outcomes; accuracy of fetal growth monitoring strategies for predicting smallness for gestational age neonates/fetal growth restriction and factors affecting the accuracy of fetal growth monitoring strategies. Methods: Nineteen databases were searched from 2000 to March 2023 and were updated September 2023. Pregnant people with and without risk factors were included. Each review question had further eligibility criteria. For accuracy results, summary estimates of the sensitivity and specificity with 95% confidence intervals for the prediction of smallness for gestational age at delivery were calculated. Random-effects models were used for the meta-analysis of clinical outcomes. Further outcomes, including the results of risk of bias assessments, were summarised narratively. Results: Fifty-eight studies (78 publications) were included in the review. Q1 - Antenatal identification of smallness for gestational age pregnancies was associated with increased rates of intervention (two retrospective cohort studies, Limitations and conclusions: There is limited evidence linking fetal growth monitoring tests results to the changes in fetal/neonatal outcomes. There is some evidence supporting the reduction of adverse outcomes by Growth Assessment Protocol implementation. Testing during the third trimester is likely to result in more accurate prediction of smallness for gestational age at birth than earlier testing. Use of a locally derived reference chart for estimated fetal weight may result in optimised sensitivity for a given birthweight reference chart (definition of smallness for gestational age). Future work: Large diagnostic cohort studies and comparative studies are needed to further examine whether and how fetal growth monitoring testing and implementation of guidance can affect clinical outcomes. Study registration: This study is registered as PROSPERO CRD42023408030. Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Evidence Synthesis programme (NIHR award ref: NIHR135862) and is published in full in