Performance of six birth‐weight and estimated‐fetal‐weight standards for predicting adverse perinatal outcome: a 10‐year nationwide population‐based study

Abstract

Objective To evaluate three birth‐weight (BW) standards (Australian population‐based, Fenton and INTERGROWTH‐21st) and three estimated‐fetal‐weight (EFW) standards (Hadlock, INTERGROWTH‐21st and WHO) for classifying small‐for‐gestational age (SGA) and large‐for‐gestational age (LGA) and predicting adverse perinatal outcomes in preterm and term babies. Methods This was a nationwide population‐based study conducted on a total of 2.4 million singleton births that occurred from 24 + 0 to 40 + 6 weeks' gestation between 2004 and 2013 in Australia. The performance of the growth charts was evaluated according to SGA and LGA classification, and relative risk (RR) and diagnostic accuracy based on the areas under the receiver‐operating‐characteristics curves (AUCs) for stillbirth, neonatal death, perinatal death, composite morbidity and a composite of perinatal death and morbidity outcomes. The analysis was stratified according to gestational age at delivery (< 37 + 0 vs ≥ 37 + 0 weeks). Results Following exclusions, 2 392 782 singleton births were analyzed. There were significant differences in the SGA and LGA classification and risk of adverse outcomes between the six BW and EFW standards evaluated. For the term group, compared with the other standards, the INTERGROWTH‐21st BW and EFW standards classified half the number of SGA (< 10th centile) babies (3–4% vs 7–11%) and twice the number of LGA (> 90th centile) babies (24–25% vs 8–15%), resulting in a smaller cohort of term SGA at higher risk of adverse outcome and a larger LGA cohort at lower risk of adverse outcome. For term SGA (< 3rd centile) babies, the RR of perinatal death using the two INTERGROWTH‐21st standards was up to 1.5‐fold higher than those of the other standards (including the WHO‐EFW and Hadlock‐EFW), while the INTERGROWTH‐21st‐EFW standard indicated a 12–26% reduced risk of perinatal death for LGA cases across centile thresholds. Conversely, for the preterm group, the WHO‐EFW and Hadlock‐EFW standards identified a higher SGA classification rate than did the other standards (18–19% vs 10–11%) and a 20–65% increased risk of perinatal death in term LGA babies. All BW and EFW charts had similarly poor performance in predicting adverse outcomes, including the composite outcome (AUC range, 0.49–0.62) for both preterm (AUC range, 0.58–0.62) and term (AUC range, 0.49–0.50) cases and across centiles. Furthermore, specific centile thresholds for identifying adverse outcomes varied markedly by chart between BW and EFW standards. Conclusions This study addresses the recurrent problem of identifying fetuses at risk of morbidity and perinatal mortality associated with growth disorders and provides new insights into the applicability of international growth standards. Our findings of marked variation in classification and the similarly poor performance of prescriptive international standards and the other commonly used standards raise questions about whether the prescriptive international standards that were constructed for universal adoption are indeed app...

International versus national growth charts for identifying small and large-for-gestational age newborns: A population-based study in 15 European countries

“…Multiple single-country studies have compared Intergrowth-21st's newborn charts with national charts. Similar to our results, local birthweight charts [33] , [34] , [35] as well as Gardosi's customised model[ 36 , 37 ] have found that using Intergrowth-21st yielded a lower prevalence of SGA and a higher prevalence of LGA than national or customised charts. We add to this literature by showing that the differences in the prevalence of SGA and LGA when using international charts varied greatly between European countries and followed a geographic gradient from north to south.…”

Comparison of the performance of estimated fetal weight charts for the detection of small‐ and large‐for‐gestational age newborns with adverse outcomes: a French population‐based study

“…39 Several studies have compared IG, WHO, Hadlock and local charts and have also reported low sensitivity of the IG charts for detecting SGA fetuses. 22,23,42 For instance, a UK study reported that the cut-off for the best sensitivity for SGA <10th percentile when specificity was set at 90% was the 11th percentile for Hadlock versus the 18th percentile for INTERGROWTH-21st. 23 Other studies comparing local EFW distributions to IG and WHO in China and Italy also noted important discrepancies in fit.…”

Value of Cerebroplacental Ratio and Uterine Artery Doppler as Predictors of Adverse Perinatal Outcome in Very Small for Gestational Age at Term Fetuses

“…Nevertheless, it is important to be aware of the inaccuracy of EFW as measured by ultrasound and the matching of BW. Cohort studies on EFW reported a high intra-and interobserver variability and a detection rate of less than 50% of SGA newborns [34,35].…”