Should We Use Customized Fetal Growth Percentiles in Urban Canada? Nir Melamed, MD, MSc, Joel G. Ray, MD, MSc, Prakesh S. Shah, MD, Howard Berger, MD, John C. Kingdom, MD, FRCSC  Journal of Obstetrics and Gynaecology Canada   Volume 36, Issue 2, Pages 164-170 (February 2014) DOI: 10.1016/S1701-2163(15)30663-0 Copyright © 2014 Society of Obstetricians and Gynaecologists of Canada Terms and Conditions

Effect of adaptation of ethnicity-specific birth weight percentile curves on the rate of SGA and LGA in the population of Toronto The graph presents the distribution of birth weight at 40 weeks based on the current national (Kramer et al.37) and South Asian-specific36 birth weight curves. The actual current SGA rate (18.3%) is demonstrated by the proportion of newborns below the current national 10th percentile threshold (Kramer et al.37: males [40 weeks]—3079 g, females [40 weeks]—2955 g) in the ethnicity-specific birth weight curves.35,36 The proportion is denoted by the areas under the graph: A (light blue, 8.3%)+B (orange, 10.0%). The new SGA rate (10.0%) in the case of adaptation of the ethnicity-specific birth weight curves is demonstrated by the proportion of newborns below the new ethnicity-specific 10th percentile threshold in the ethnicity-specific birth weight curves (2906 g).35,36 The proportion is denoted by the area under the graph: B (orange, 10.0%). The actual current LGA rate (3.7%) is demonstrated by the proportion of newborns above the current national 90th percentile threshold (Kramer et al.37: males [40 weeks]—4200 g, females [40 weeks]—4034 g) in the ethnicity-specific birth weight curves (Ray et al.36). The proportion is denoted by the area under the graph: C (light blue, 3.7%). The new LGA rate (10.0%) in the case of adaptation of the ethnicity-specific BW curves is demonstrated by the proportion of newborns above the new ethnicity-specific 90th percentile threshold in the ethnicity-specific birth weight curves (4018g) (Ray et al.36). The proportion is denoted by the areas under the graph: C (light blue, 3.7%)+D (orange, 6.3%). Journal of Obstetrics and Gynaecology Canada  2014 36, 164-170DOI: (10.1016/S1701-2163(15)30663-0) Copyright © 2014 Society of Obstetricians and Gynaecologists of Canada Terms and Conditions