Predictive ability of fetal growth charts in identifying kindergarten-age developmental challenges: a cohort study

Abstract

BackgroundThe Society for Maternal-Fetal Medicine recommends defining fetal growth restriction as an estimated fetal weight or abdominal circumference below the 10th percentile of a population-based reference. However, as multiple references are available, an understanding of their ability to identify infants at increased risk due to fetal growth restriction is critical. Previous studies have focus on the ability of different population references to identify short-term outcomes, but fetal growth restriction also has longer-term consequences for child development. ObjectivesTo estimate the association between estimated fetal weight (EFW) percentiles on the INTERGROWTH-21st and WHO fetal growth charts and kindergarten-age childhood development, and establish the charts’ discriminatory ability in predicting kindergarten-age developmental challenges. Study DesignWe conducted a retrospective cohort study linking obstetrical ultrasound scans conducted at BC Women's Hospital, Vancouver, Canada, with population-based standardized kindergarten test results.The cohort was limited to non-anomalous, singleton fetuses scanned ≥ 28 weeks’ gestation, 2000-2011, with follow-up to 2017.We classified EFWs into percentiles using the INTERGROWTH-21st and WHO charts. We used generalized additive modelling to link EFW percentile with routine province-wide kindergarten readiness test results. We calculated the area under the receiver-operating characteristic curve (AUC), as well as other measures of diagnostic accuracy with 95% confidence intervals (CI) at select percentile cut-points of the charts. We repeated analyses using the Hadlock chart to help contextualize findings.The main outcome measure was the total Early Development Instrument (EDI) score (/50). Secondary outcomes were EDI sub-domain scores for language and cognitive development, and for communication skills and general knowledge; designation of ‘developmentally vulnerable’ or ‘special needs’. ResultsAmong 3418 eligible fetuses, those with lower EFW percentiles had systematically lower EDI scores and increased risks of developmental vulnerability. However, the clinical significance of differences was modest in magnitude: e.g., total EDI score -2.8 [95% CI: -5.1, -0.5] in children with an EFW 3-9th percentile of INTERGROWTH chart (vs. reference of 31-90th). The charts’ predictive abilities for adverse child development were limited (e.g., AUC<0.53 for all 3 charts). ConclusionsLower EFW percentiles on the INTERGROWTH-21st and WHO charts indicate increased risks of adverse kindergarten-age child development at the population level, but are not accurate individual-level predictors of adverse child development.