Abstract: Objective To establish population-based body mass index (BMI) centiles for gestational age specific newborns. Methods All the newborns born in Shunyi District Hospital and Shunyi Maternal and Child Hospital during 1 November 2009 to 21 January 2011 were taken standard measurement of birth weight and length.The newborns meeting the criteria were selected to create database.K-median-coefficent of variation method was used to smooth the percentile curves.Comparison was made with a Brazil's research. Results Percentiles at P₃, P₁₀, P₂₅, P₅₀, P₇₅, P₉₀, P₉₃ of BMI were calculated, the curves for each gestational age were successfully smoothed.Differences of BMI between genders were not statistically significant.The BMI values for gestational age in all percentiles showed a steady increase up to 38 weeks, levels off up to the 40^th week, followed by a slight decrease to the 42^nd week in both genders. Conclusion Recent percentiles for gestational age specific BMI of newborns are presented in this research, and it can be used as a BMI normative reference for the local clinicians.

Key words: gestational age, newborn, body mass index, smoothed percentiles

摘要： 目的 建立以人群为基础的胎龄别新生儿体质指数(body mass index, BMI)百分位数修匀曲线。方法 对2009年11月1日-2011年1月21日期间在北京市顺义区医院和顺义区妇幼保健院出生的新生儿进行体重和身长的标准化测量, 采用偏度-中位数-变异系数法修匀其出生BMI百分位数, 并进行不同地区研究间的比较。结果 获得顺义区胎龄别新生儿BMI修匀曲线, 不同性别间差异无统计学意义(P＞0.05), BMI随胎龄增长呈现升高-平缓-轻微降低的趋势, 中国新生儿BMI正常范围低于巴西新生儿。结论 本研究建立了北京市顺义区胎龄别新生儿BMI百分位数修匀曲线, 可以为新生儿出生体格发育评价提供新的参考依据。

关键词: 胎龄, 新生儿, 体质指数, 修匀百分位数