Oken Emily, Kleinman Ken P, Rich-Edwards Janet, Gillman Matthew W
Department of Ambulatory Care and Prevention, Harvard Medical School and Harvard Pilgrim Health Care, Boston, USA.
BMC Pediatr. 2003 Jul 8;3:6. doi: 10.1186/1471-2431-3-6.
Fully understanding the determinants and sequelae of fetal growth requires a continuous measure of birth weight adjusted for gestational age. Published United States reference data, however, provide estimates only of the median and lowest and highest 5th and 10th percentiles for birth weight at each gestational age. The purpose of our analysis was to create more continuous reference measures of birth weight for gestational age for use in epidemiologic analyses.
We used data from the most recent nationwide United States Natality datasets to generate multiple reference percentiles of birth weight at each completed week of gestation from 22 through 44 weeks. Gestational age was determined from last menstrual period. We analyzed data from 6,690,717 singleton infants with recorded birth weight and sex born to United States resident mothers in 1999 and 2000.
Birth weight rose with greater gestational age, with increasing slopes during the third trimester and a leveling off beyond 40 weeks. Boys had higher birth weights than girls, later born children higher weights than firstborns, and infants born to non-Hispanic white mothers higher birth weights than those born to non-Hispanic black mothers. These results correspond well with previously published estimates reporting limited percentiles.
Our method provides comprehensive reference values of birth weight at 22 through 44 completed weeks of gestation, derived from broadly based nationwide data. Other approaches require assumptions of normality or of a functional relationship between gestational age and birth weight, which may not be appropriate. These data should prove useful for researchers investigating the predictors and outcomes of altered fetal growth.
要全面了解胎儿生长的决定因素和后遗症，需要对根据胎龄调整后的出生体重进行连续测量。然而，美国已公布的参考数据仅提供了每个胎龄出生体重的中位数、最低和最高第5和第10百分位数的估计值。我们分析的目的是创建更连续的胎龄出生体重参考测量值，用于流行病学分析。
我们使用了美国最新全国出生数据集的数据，以生成妊娠22至44周每个完整孕周出生体重的多个参考百分位数。胎龄根据末次月经确定。我们分析了1999年和2000年出生于美国常住母亲的6,690,717名单胎婴儿的记录出生体重和性别的数据。
出生体重随着胎龄增加而上升，在孕晚期斜率增加，40周后趋于平稳。男孩的出生体重高于女孩，晚出生的孩子体重高于头胎，非西班牙裔白人母亲所生婴儿的出生体重高于非西班牙裔黑人母亲所生婴儿。这些结果与之前公布的有限百分位数估计结果非常吻合。
我们的方法提供了妊娠22至44周完整孕周出生体重的综合参考值，这些值来自广泛的全国性数据。其他方法需要假设正态性或胎龄与出生体重之间的函数关系，这可能并不合适。这些数据应该对研究胎儿生长改变的预测因素和结果的研究人员有用。
