Statistical analysis
LGA
REGRESSION
Demographic data were summarized as n (%) or mean (± SD). We developed a fetal growth percentile customization model using the Gardosi method [In a third customization model, we calculated customized percentiles directly using quantile regression with monotonic smoothing, a flexible model that does not assume a normal distribution [The customization method of fetal growth based on the previously noted 6 maternal and fetal factors calculates the term optimal weight at 40 weeks which is then extrapolated back to ultrasound EFW across gestation using the Hadlock reference, proportionately adjusting the percentiles (e.g., 10Both the heteroscedastic regression model with separately customizable mean and standard deviation and the quantile regression model that explicitly produced customized percentiles were then compared to the Gardosi model [We also compared the performance of the three customization models (Gardosi, heteroscedastic and quantile regression) and the Duryea birthweight reference in relation to SGA and LGA birthweight with neonatal morbidity and mortality [All analyses were completed with the use of SAS software (version 9·4, SAS Institute, Inc., Cary, NC) or R (version 3·5·2, available at 