A New Birthweight Reference by Gestational Age: A Population Study Based on the Generalized Additive Model for Location, Scale, and Shape Method

BackgroundIt is important to choose a suitable birthweight reference to assess newborns, especially those that are small for gestational age (SGA). Currently, there is no regional standard reference for the north of China or for Shandong province. MethodsA total of 130,911 data records of singleton, live neonates born at 24-42 weeks of gestation were collected from 2016 to 2018 in Shandong province. A new birthweight-for-gestational age percentile reference was constructed based on the Generalized Additive Model for Location, Scale and Shape (GAMLSS) package in R version 3.5. The established gestational age weight curve was compared separately with the Fenton curve, INTERGROWTH-21st curve, and the Chinese Neonatal Network Standard curve of 2015. ResultsWe established the reference values of birthweight by gestational age at the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles. Newborns had much heavier birthweights than those in the INTERGROWTH-21st and Fenton curves at most gestational ages. Although the newborns' birthweight references were closer to the Chinese Neonatal Network Standard except a few for gestational age, this study and INTERGROWTH-21st had similar birthweight curve shapes. ConclusionsThere are obvious differences among the criteria for newborn birthweights. Therefore, it is more accurate to assess newborns using the local birthweight reference.

Automated summary

Choosing a suitable birthweight reference is important for assessing newborns. This study constructed a new birthweight-for-gestational age percentile reference and compared it with other existing standards. The results showed that newborns had heavier birthweights compared to other standards, although it was closer to the Chinese Neonatal Network Standard. The study also found similarities between the birthweight curve shape of this study and the INTERGROWTH-21st standard.