Comparison of Postnatal Growth Charts of Singleton Preterm and Term Infants Using World Health Organization Standards at 40–160 Weeks Postmenstrual Age: A Chinese Single-Center Retrospective Cohort Study

Abstract

There remains controversy regarding whether the growth charts constructed from data of term infants, such as those produced by the World Health Organization (WHO) standards, can appropriately evaluate the postnatal growth of preterm infants. This retrospective cohort study, conducted in the First Affiliated Hospital of Shandong First Medical University in Jinan China, aimed to compare the postnatal growth charts of singleton preterm and term infants using WHO standards at 40–160 weeks postmenstrual age (PMA). A total of 5,459 and 15,185 sets of longitudinal measurements [length/height, weight, head circumference (HC), and body mass index (BMI)] from birth to 160 weeks PMA were used to construct growth charts for 559 singleton preterm (mean PMA at birth, 33.84 weeks) and 1,596 singleton term infants (born at 40 weeks PMA), respectively, using the Generalized Additive Models for Location, Scale, and Shape (GAMLSS) method. Z-scores (prematurity corrected) were calculated using WHO Anthro software. Compared to WHO standards, all parameters of preterm infants were increased, especially in terms of length/height and weight; the gap between the two almost spanned two adjacent centile curves. Compared to term controls, the length/height, weight, and BMI of preterm infants were higher at 40 weeks PMA, surpassed by term infants at 52–64 weeks PMA, and quite consistent thereafter. The HC of preterm infants at 40–160 weeks PMA was quite consistent with both term controls and the WHO standards. The Z-scores for length/height, weight, and BMI of preterm infants relative to the WHO standards gradually decreased from 1.20, 1.13, and 0.74 at 40–44 weeks PMA to 0.67, 0.42, and 0.03 at 132–160 weeks PMA, respectively; Z-scores for HC of preterm infants rapidly decreased from 0.73 to 0.29 at 40–50 weeks PMA, and then fluctuated in the range of 0.08–0.23 at 50–160 weeks PMA. Preterm infants had higher growth trajectories than the WHO standards and similar but not identical trajectories to term infants during the first 2 years of life. These findings reemphasize the necessity of constructing local growth charts for Chinese singleton preterm infants.

Longitudinal Follow-Up on the Growth Rates and Influence Factors of Preterm and Full-Term Infants in Urban Areas of Hubei Province: A Birth Cohort Study

“…During the rst year of age, there were signi cant differences in the growth rates of length and weight of preterm and full-term infants at different stages. The growth rates of preterm infants were signi cantly lower than those of full-term infants from birth to 3 months, and gradually caught up to the level of fullterm infants after 3 months [20]. Speci cally, the growth rates of preterm and full-term infants were attributed to the regulatory mechanism of growth hormone (GH), insulin-like growth factor-1 (IGF-1), and insulin-like growth factor binding protein-3 (IGFBP-3).…”

Differences in Postnatal Growth of Preterm Infants in Northern China Compared to the INTERGROWTH-21st Preterm Postnatal Growth Standards: A Retrospective Cohort Study

“…Nevertheless, whether the actual postnatal growth of a specific preterm population differs from that of the IPPGS determines the interpretation of the growth assessment results with the IPPGS and subsequent clinical decisions, such as the optimal time point to terminate fortified nutrition. In addition, our previous studies demonstrated higher growth levels among preterm infants in Shandong, China, than those indicated by the Fenton reference and WHO standards before the corrected age of 2 years old ( 22 , 23 ). Therefore, we hypothesized that this preterm population might also have higher postnatal growth levels than those of the IPPGS.…”

“…Recently, emerging studies have proposed that disparities exist in growth between specific preterm populations and international growth standards/references. For example, our previous study proved that singleton preterm infants had higher growth levels than that of WHO standards but had similar growth levels to term infants in the same center from corrected term to 2 years of age ( 23 ). A multicenter cohort study conducted in Sichuan, China, demonstrated that preterm infants had higher growth levels than those of the IPPGS and WHO standards and had consistent growth with their term counterparts after 3 months of corrected age ( 21 ).…”

“…Therefore, the distribution curve tends to be stable, even if the sample size is small. GAMLSS was chosen to create these growth charts because it had a more accurate prediction ability, a smoother curve, and more effective use in our previous study ( 23 , 29 ) and the other studies in China ( 30 , 31 ) and other countries ( 32 , 33 ). Our reference data showed that the data distribution was well-fitted in GAMLSS using the Q-Q plot, worm plot, and residual plot.…”

The growth rates and influencing factors of preterm and full-term infants: A birth cohort study

“…[20] During the first year of life, there were significant differences in the growth rates of the length and weight of preterm and full-term infants at different stages. [21] Specifically, the growth rates of preterm and full-term infants have been attributed to the regulatory mechanism of growth hormone, insulin-like growth factor-1 (IGF-1), and insulin-like growth factor binding protein-3 (IGFBP-3). As for the regulatory mechanism, growth hormone was an important regulator for the growth rates of preterm infants in a pulsed pattern, and IGF-1 formed a complex with IGFBP-3 which was closely related to the growth rates of preterm infants.…”