Prematurity is becoming more frequent nowadays especially with the development of artificial fertilization methods 1. In 2016, the Center for Disease Control and Prevention (CDC) declared that around one baby out of 10 is born premature 2,3. Newborn’s growth is an important marker and a screening method for a number of pathologies or deficiencies 4, which needs to be tracked through growth charts. The latter would lead to a better monitoring of the nutritional status, thus, may limit the depth and duration of diet-related growth restriction and its short- and long-term damages thereafter 3.
In fact, many charts have been developed, mostly based on intrauterine growth and rarely adapted to preterm newborns. Indeed, preterm babies are not fetuses as they no longer live in-utero 5. Regardless of their apparent independence, they have not acquired the growth and survival skills of full-term babies yet and present a physiological immaturity. Consequently, when assessed via common growth charts, these newborns remain under the 10th percentile for a long time and do not catch up with normal growth until the age of two to three years. For this motive, the actual trend is to supplement this population with a hypercaloric nutrition to compensate for this extra-uterine growth restriction. Despite this supplementation, most babies fail to reach their set growth goals still.
Within that scope, alarming studies have shown an association between prematurity and obesity in adulthood, with question marks raised about the link between "overfeeding" the preterm newborns, obesity and cardiovascular complications later in life 6. In the neonatal population aged between 36 and 50 weeks of unadjusted age, the Fenton chart is considered one of the best charts for assessing longitudinal growth 7. Nevertheless, it showed two weaknesses: it does not reflect the adaptation of the premature newborn to extra-uterine life and it under- or overestimates newborn’s growth.
The most commonly used chart at the Notre Dame des Secours University Hospital Center-Byblos (CHU-NDS), is the Fenton chart 2003, which has not been updated till now. Between 2009 and 2014, the Intergrowth21 project has emerged as a successful growth chart and underwent rigorous processes that ensured that the data collected in the INTERGROWTH‐21st project is of exceptionally high quality 8. Intergrowth-21 charts are used to create standards for postnatal growth of premature infants especially those born before 32 gestational weeks 9. While disagreements on the Fenton charts continue, the results of the Intergrowth 21st project were awaited with great interest. The "Intergrowth 21st Project" was a prospective multicenter, multi-ethnic study, which included low-risk women, non-smokers, with a normal pregnancy history, and no health problems that could affect fetal growth 10. All maternal health care and nutritional needs were met. Birth and postnatal growth standards were developed from data collected from a cohort of uncomplicated pregnancies with normal growing fetuses 11. These very strict selection criteria were mandatory, in order to create standards on how the normal growth of healthy premature babies should be.
In a recent systematic review, 61 longitudinal reference charts were identified and compared to the Intergrowth-21 chart 9; assessments made using the Intergrowth-21 charts demonstrated a reduction in the diagnosis of extrauterine growth retardation 9,12. Many infants who were classified as having restricted growth according to the Fenton charts, turned out to have normal postnatal growth according to the Intergrowth-21 charts 12. Another important point is that, like the World Health Organization (WHO) growth standards, the Intergrowth-21 growth standards aim at producing graphs that describe optimal rather than average growth, which could be used worldwide.
Being in a developing country, a local validation before adapting Intergrowth-21 charts to our new born infants is necessary, especially to avoid the misclassification of their size, which may have an impact on their nutritional support. For these reasons, the objective of this study was to check which method (the universal Fenton 2003 curves or the Intergrowth-21 curves) used in the neonatology department at CHU-NDS would predict height, weight and cranial perimeter of premature Lebanese babies better. This study would help us evaluate the difference between both curves in terms of extra- and intra-uterine growth restriction, reflected by weight, height and head circumference at birth and verify later the convergence between the intergrowth-21 and the WHO curves of the child health record book around the sixth month of life.