Estimated fetal weight percentiles and kindergarten-age child
development: evaluating the predictive ability of the INTERGROWTH-21st
and WHO fetal growth charts a cohort study
Objectives: To estimate the association between estimated fetal weight
(EFW) percentiles on the INTERGROWTH-21st and WHO fetal growth charts
and kindergarten-age childhood development, and identify the charts’
percentile cut-offs that best predict kindergarten-age developmental
challenges. Design: Retrospective cohort linkage study. Setting:
Obstetrical ultrasound department of BC Women’s Hospital, Vancouver,
Canada. Population or Sample: Non-anomalous, singleton fetuses scanned ≥
28 weeks’ gestation, 2000-2011 (n=3418). Methods: 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
AUC, as well as other measures of diagnostic accuracy with 95%
confidence intervals (CI) at select percentile cut-points of the charts.
Main Outcome Measures: Total Early Development Instrument (EDI) score
(/50). Secondary outcomes: EDI sub-domain scores for language and
cognitive development, and for communication skills and general
knowledge; designation of ‘developmentally vulnerable’ or ‘special
needs’. Results: Fetuses 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 both
charts). Conclusions: Lower 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.