Arbuckle T E, Wilkins R, Sherman G J
Department of Epidemiology, University of North Carolina, Chapel Hill.
Obstet Gynecol. 1993 Jan;81(1):39-48.
To develop current birth weight norms by gestational age for singleton and twin births in Canada.
Birth weight data were obtained from vital statistics and health department birth registrations for over one million live births in Canada from 1986-1988. Unlikely combinations of birth weight and gestational age were defined within each stratum of multiplicity, gender, and gestational age as records with birth weights more than two interquartile ranges above the 75th percentile or below the 25th percentile. Birth weight percentiles (from first to 99th) by gestational age and sex were calculated for singleton and twin live births.
Of the total records, 0.4% were missing data on birth weight or gestational age, and an additional 0.4% were identified as extreme outliers and were excluded from the analysis. Charts of birth weight by gestational age show percentiles 1, 3, 5, 10, 25, 50, 75, 90, 95, 97, and 99 by sex for singleton and twin live births.
The large data base assembled for this analysis provides current, stable birth weight-gestational age percentiles for classifying newborns from a developed country as small, appropriate, or large for gestational age. Compared with birth weight distributions from the 1970s, these current norms are heavier for full-term infants and the interdecile range for preterm infants is narrower. We recommend that birth weight norms be updated every 5-10 years.
制定加拿大单胎和双胎分娩按胎龄划分的当前出生体重标准。
出生体重数据取自1986 - 1988年加拿大超过100万例活产的人口统计数据和卫生部门的出生登记记录。在多胎、性别和胎龄的每个分层中，将出生体重与胎龄的不太可能组合定义为出生体重高于第75百分位数或低于第25百分位数两个四分位距以上的记录。计算单胎和双胎活产按胎龄和性别的出生体重百分位数（从第1到第99百分位数）。
在所有记录中，0.4%缺少出生体重或胎龄数据，另外0.4%被确定为极端异常值并被排除在分析之外。按胎龄划分出生体重的图表显示了单胎和双胎活产按性别的第1、3、5、10、25、50、75、90、95、97和99百分位数。
为该分析收集的大型数据库提供了当前稳定的出生体重 - 胎龄百分位数，用于将发达国家的新生儿分类为小于胎龄、适于胎龄或大于胎龄。与20世纪70年代的出生体重分布相比，这些当前标准中足月儿体重更重，早产儿的十分位数范围更窄。我们建议每5 - 10年更新一次出生体重标准。
