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 :