关键词: 胎龄, 新生儿, 体质指数, 修匀百分位数

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