Introduction
The Society for Maternal-Fetal Medicine recommends that fetal growth restriction should be defined as an estimated fetal weight (EFW) or abdominal circumference below the 10th percentile of a population-based fetal growth reference. However, multiple population-based fetal growth references exist, and it is unclear which chart should be used. The fetal growth reference conventionally used in the United States, Hadlock’s, was derived from a population of 392 predominantly middle-class white women who delivered over 30 years ago and has a number of methodological limitations. Although several new, high-quality population-based fetal growth charts that overcome the methodological limitations of existing charts have recently been published, such as the WHO fetal growth chart and the INTERGROWTH-21st fetal growth chart, research to date has yet to convincingly identify which chart- and which percentile cut-off on the chart- best predicts high-risk infants.
Most studies have focused on evaluating the new fetal growth charts in relation to neonatal health outcomes such as small-for-gestational age birth and adverse perinatal outcomes. However, fetal growth restriction also has longer-term consequences, and children with fetal growth restriction are also more likely to experience school-age developmental deficits than their normally-grown peers. While decisions about timing of delivery are likely to be made based on more immediate perinatal risks and outcomes, determination of which chart to use, and optimal thresholds on the charts, should also take these longer-term outcomes, which are important families, into account.
The goals of this study were to 1) estimate the association between estimated fetal weight percentiles on the INTERGROWTH-21st and WHO fetal growth charts and kindergarten-age childhood development, and 2) establish the percentile cut-offs on the INTERGROWTH-21st and WHO fetal growth charts that best identify fetuses at risk for developmental challenges at kindergarten age.
Methods :