Postnatal length and weight growth velocities according to Fenton reference and their associated perinatal factors in healthy late preterm infants during birth to term-corrected age: an observational study

Abstract

BackgroundOptimum early postnatal growth is critical for early and later health of preterm infants. Postnatal length and weight growth velocities and their associated perinatal factors in healthy late preterm infants without restriction of neonatal complications and nutritional problems have not been widely studied.MethodsAs part of ongoing longitudinal follow-up study of growth and development of preterm infants in Shandong Qianfoshan Hospital in China, 599 healthy late preterm infants without neonatal complications and nutritional problems were sampled from 795 preterm infants born in January 2014 to April 2017. Perinatal factors, growth parameters, growth velocities(ΔLengthZ and ΔWeightZ: Z-score changes of length and weight) during birth and term-corrected age were documented. Associated variables of growth velocities were analyzed by bivariate and multivariate regression analyses. Adjusted ΔLengthZ and ΔWeightZ were compared between/among subgroups of associated variables using analysis of covariance. Catch-up growth were defined as ΔLengthZ or ΔWeightZ > 0.67.ResultsThe mean ΔLengthZ and ΔWeightZ were 0.28, 0.65, respectively. Catch-up growth of length and weight was ubiquitous(30.7, 46.2%, respectively). Faster length growth velocity was associated with male, larger postmenstrual age(PMA) at birth, younger mother and larger PMA at visit; Faster weight growth velocity was associated with male, unfavorable intrauterine growth status defined by birth weight percentile(Small-for-Gestational-Age(<P10), Appropriate-for-Gestational-Age(P10–90), Large-for-Gestational-Age(>P90)), twin and larger PMA at visit. When adjusted for associated co-variables, weight catch-up growth existed in subgroups of 36 weeks PMA at birth, male, twin and SGA, while AGA almost reached this standard with mean adjusted ΔWeightZ as 0.66. Although none of these subgroups got length catch-up growth standard, infants of 36 weeks PMA at birth had statistically rapider length growth velocity than 34 and 35 weeks PMA at birth subgroups(mean adjusted ΔLengthZs of 34, 35 and 36 weeks subgroups: 0.10, 0.22, 0.38, respectively).ConclusionsPostnatal length and weight growth velocities of healthy late preterm infants from birth to term-corrected age were much superior than that of Fenton reference, especially for weight, with ubiquitous catch-up growth. Different associated factors for length and weight growth signified the necessity of constructing more detailed growth standards by specific stratification for associated factors.

Body weight changes of preterms in the postnatal period

“…Zhang et al found that male preterms gained significantly more weight than females [6]. However, in our study, although the mean birth weight in male preterms was significantly higher than that of girls, no significant difference was found between the genders in terms of weight gain ratios within the first, 3rd, 7th, 15th and 30th days after birth.…”

“…This might be caused by the high rate of loss of the newborns due to the concomitant diseases. In addition, it was reported that mortality rates in those below 1500 grams would reach 60% [4][5][6]. In our study, this rate in the newborns below 1500 grams was found to be only 11.8%, which was significantly higher than the mortality rate (1.0%) in those over 1500 grams.…”

“…Because postnatal development patterns are closely related to health status, they are important, especially in preterm newborns. It has been reported that the postnatal development curve in preterm newborns can be affected by regional, local, ethnic and traditional factors as well as factors such as gestational week, gender, anthropometry of parents, nutritional conditions, presence of concomitant diseases [6][7][8][9]. Therefore, this comprehensive study of preterms is important in terms of presenting data that can contribute to the literature for our country.…”

Extrauterine growth restriction in extremely preterm infants based on the Intergrowth-21st Project Preterm Postnatal Follow-up Study growth charts and the Fenton growth charts

“…Vermont Oxford Network study reported that EUGR below the 10th percentile of weight by the Fenton growth chart occurred in half of VLBW infants [22]. The definition of EUGR as the change in z scores also has been used, and a study using the Fenton chart reported the prevalence of EUGR during NICU admission in preterm infants born at GA of 22-32 weeks as 47% in 2005 and 38% in 2012 [4,23]. EUGR defined by the Fenton chart in the present study seemed higher than those reports, but the study population was less mature in our study compared with those in the aforementioned studies.…”

Postnatal Growth of Preterm Infants During The First Two Years of Life: Catch-Up Growth Accompanied by Risk of Overweight

“…Our study noticed that growth trajectories of preterm infants were consistent over the WHO standards from CA 40 weeks to CA 24 months, especially for weight. Recent studies in Chinese population also found that growth rate in preterm infants was higher than that in term infants during the rst year of life (17,18). Several possible reasons might explain this phenomenon.…”