Growth standard curves of birth weight, length and head circumference of Chinese newborns of different gestation

Abstract

Objective: To study and formulate the growth standards for birth weight, length and head circumference of Chinese newborns of different gestation. Methods: A cross-sectional survey was carried out by the stratified cluster sampling method from June 2015 to November 2018 in 13 cities including Beijing, Harbin, Xi'an, Shanghai, Nanjing, Wuhan, Guangzhou, Fuzhou, Kunming, Tianjin, Shenyang, Changsha and Shenzhen. A total of 24 375 newborns with gestational age between 24 to 42 weeks were included. The standard percentile-curves of birth weight, length and head circumference for newborn boys and girls in gestational weeks 24 to 42 were established by the generalized additive model for location, scale and shape (GAMLSS). The new reference standard developed in this study was compared with the reference values of China in 1988 and the international Fenton 2013. Results: Among the 24 375 newborns (13 197 males (54.1%),11 178 females (45.9%)), 12 264 were preterm infants and 12 111 were full term infants. The 3(rd), 10(th), 25(th), 50(th), 75(th), 90(th) and 97(th) percentile reference values and curves of birth weight, length and head circumference were obtained for male and female newborns from 24 to 42 gestation weeks. The data showed that birth weight, length and head circumference increased rapidly with the gestational age, but the growth velocity decreased slightly from 37 weeks. For example, the median birth weight for males at 28 weeks, 32 weeks, 37 weeks and 40 weeks was 1 154, 1 805, 2 943 and 3 455 g, respectively. The birth weight, length and head circumference of males at all gestational ages were 87-133 g, 0.2-0.9 cm and 0.3-0.6 cm higher than those of females, respectively. Compared with the percentile curves of birth weight of Chinese reference in 1988, there were significant differences regarding the percentile lines of males and females, especially the 10(th), 50(th), and 90(th) percentile values of birth weight were significantly higher than the reference values in 1988 from 37 to 42 gestation weeks. For example, the median birth weight at 40 weeks in the study was 115-242 g higher than that in 1988. Compared with the standard reference of Fenton 2013, the reference curve at 50(th) percentile of birth weight in this study was 13-81 g slightly higher than that of Fenton 2013 before 33 weeks, and then it was gradually lower than that of Fenton 2013 and the difference was 148-367 g at 41 to 42 weeks of gestation. The 10(th) percentile curve of Fenton 2013 was 11-64 g lower than that of this study in both males and females before 40 weeks. Conclusions: This study created a new national growth standard of birth weight, body length and head circumference for Chinese neonates at 24 to 42 weeks of gestation, which can be used for the growth and nutrition evaluation of newborns at birth and preterm infants in the early postnatal period. The 10(th) percentile and the 3(rd) percentile of growth standards could be suggested as the cut-off point for identifying small for gestational age and severe small for gestational age, respectively.