目的 考普指数（Kaup index，KI）用于评估新生儿身体充实度和营养状况。该研究旨在调查胎龄27~42周新生儿出生时的KI值，制定其百分位曲线。方法 采用横断面时间段整群抽样实况调查方法，于2013年4月至2015年9月在深圳市两家医院完成了16 887例胎龄27~42周单胎新生儿体重、身长的现场测量，用以计算KI值，并制定不同胎龄新生儿的KI百分位曲线。结果 获得了胎龄27~42周单胎新生儿男、女、性别混合三分组KI均数和标准差，并制定了其3rd~97th百分位曲线。胎龄27周者KI的50th曲线值最低，随着胎龄增加KI值不断增大；各胎龄组男性KI的50th曲线值高于女性。各胎龄组（除胎龄33周外）男性KI的均数高于女性，其中胎龄34周及36~40周KI均数男性与女性间的差异有统计学意义（P < 0.05）。结论 新生儿出生时KI值随胎龄增加而增大，提示随胎龄增加人体密度和充实度不断提高；男性新生儿出生时身体充实度好于女性。该研究制定的胎龄27~42周单胎新生儿男、女、性别混合三分组KI百分位曲线可为深圳新生儿出生时身体充实度和营养状况的评估提供参考。

Objective To study the Kaup index (KI), an index used to evaluate body burliness and nutritional status, of neonates with a gestational age (GA) of 27-42 weeks at birth, and to establish the percentile curves of KI. Methods Cross-sectional cluster sampling was performed from April 2013 to September 2015 to select 16 887 singleton neonates with a GA of 27-42 weeks in two hospitals in Shenzhen, China. Body weight and body length were measured to calculate KI. The percentile curves of KI were plotted in these neonates. Results Mean KIs and corresponding standard deviations were obtained for singleton neonates with a gestational age of 27-42 weeks (in male, female, and mixed groups), and the 3rd-97th percentile curves of KI were plotted. The singleton neonates with a GA of 27 weeks had the lowest 50th percentile value of KI, and KI gradually increased with GA. Boys had a higher 50th percentile value of KI than girls in each GA group. In all groups except the 33-week GA group, boys had a higher mean KI than girls, and there was a significant difference in the mean KI between boys and girls in the GA groups of 34 and 36-40 weeks (P < 0.05). Conclusions KI of neonates at birth increases with GA, suggesting that body density and body burliness increase with GA. Boys have better body burliness than girls at birth. The percentile curves of KI plotted for singleton neonates with a GA of 27-42 weeks (in male, female, and mixed groups) can provide a reference for evaluating the body burliness and nutritional status of neonates at birth in Shenzhen.