Diagnostic accuracy of customized foetal growth charts in the detection of adverse perinatal outcome of term small for gestational age foetuses

Abstract

Abstract Purpose To determine the diagnostic accuracy of Peruvian customized foetal growth charts in the detection of adverse perinatal outcome (APO) in term small for gestational age (SGA) fetuses. Methods This was an observational, cross-sectional, case‒control study, with 555 pregnant women treated at a hospital in Lima, Peru, whose foetal weights were evaluated by Peruvian charts and growth standards of the World Health Organization (WHO), Fetal Medicine Foundation (FMF), Hadlock and INTERGROWTH-21st Project (IG21). Results The prevalence of SGA using the Peruvian charts was 10.5%, and the OR was 9.9, with an effect size > 0.8. The PPV of the Peruvian char (52.5%) was higher than those of the Hadlock and FMF standards. The NPV (90%) was higher than that of the FMF standard. The LR + was 5.8, with strong evidence to confirm the diagnosis, but with an LR- = 0.6. The performance of the Peruvian charts in predicting APO was poor (AUC = 0.688), but they performed well in predicting an Apgar score < 7 at 5 minutes (AUC = 0.852), outperforming the WHO and FMF standards. Conclusion Peruvian customized charts more accurately estimated the prevalence of SGA and had a large effect size for the association between SGA and APO. The diagnostic metrics support the use of the Peruvian charts as a diagnostic and prognostic test in which the probability of APO is reduced when the diagnosis of SGA is excluded, and also as a test with a good ability to predict an Apgar score < 7 at 5 minutes.