The Relationship of Poor Linear Growth Velocity with Neonatal Illness and Two-Year Neurodevelopment in Preterm Infants

Abstract

Background: Poor postnatal weight gain in very low birth weight (VLBW) preterm infants has been shown to have a negative effect on neurodevelopment. However, the dose-dependent neurodevelopmental consequences of linear stunting in this population have not previously been assessed. Understanding this relationship is important because organ growth and differentiation are more tightly linked to lean body mass and thus linear growth. Objective: To assess the duration and clinical determinants of poor linear growth and its relationship to neurodevelopment in preterm infants. Methods: Weight, recumbent length and head circumference were recorded at birth, hospital discharge, and at 4, 12 and 24 months corrected age (CA) in 62 VLBW infants. Standardized Z-scores for weight (WZ), length (LZ) and head circumference (HCZ) were calculated and assessed as a function of inpatient clinical factors using linear regression models. Twenty-four-month neurodevelopmental function was analyzed as a function of growth status. Results: Mean LZ was lower than WZ (p = 0.004) at hospital discharge, was related in part to illness severity and remained lower than baseline LZ until 24 months CA. Controlling for WZ and HCZ at each age, lower LZ at 4 and 12 months CA was associated with lower cognitive function scores at 24 months CA (p ≤ 0.03). Conclusions: Nutritional and nonnutritional factors influenced the degree of pre- and postdischarge linear growth suppression in VLBW infants, which in turn was negatively associated with developmental outcomes at 24 months CA. Since linear growth correlates with brain growth and indexes a number of clinical factors, it is an important biomarker that can be used in VLBW infants to predict long-term developmental outcomes.

BMI Curves for Preterm Infants

“…13,22 Although extrauterine growth restriction usually refers to weight growth restriction, it also affects head and especially length growth. 9,16,19,20 Poor growth in weight, length, or head circumference is associated with poor neurodevelopmental outcomes. 21,[41][42][43] The relationships between poor growth and poor neurodevelopment are well documented for weight and head circumference, 9,21,[41][42][43] and recently a study of AGA, very low birth weight (,1500 g at birth) infants by Ramel et al 9 found a significant relationship between poor linear growth and poor neurodevelopment scores at 24 months.…”

“…In preterm infants, concern about rapid postnatal growth, fat accumulation, and their potential adverse effects has increased interest in the composition and proportionality of postnatal growth. [5][6][7][8][9][10][11][12] Because there is no routine clinical measurement of body composition in the NICU setting, a proxy such as BMI could be a useful clinical tool for preterm infants.…”

“…There is evidence that preterm infants experience poor growth postnatally, 9,[16][17][18][19][20][21] and upon closer look this growth failure is disproportionate between growth measures 9,20,22 : head growth is best, weight growth is slower and the focus of concern, but gain in length is slowest. 9 Currently there is no way to quantify and monitor disproportionate growth in the NICU. An infant's weight-for-age and length-for-age percentiles may be compared, but a weight-for-length ratio provides a simple, objective, and more accurate method of identifying, quantifying, and tracking disproportionate growth by comparing weight relative to length in 1 parameter.…”

Antenatal and Postnatal Growth and 5-Year Cognitive Outcome in Very Preterm Infants

“…1,[6][7][8] Suboptimal growth at the time of discharge is still a common phenomenon despite advances in treatment and nutrition regimens, [9][10][11] and growth delay, especially in weight 8,12,13 and length, 8,14,15 usually remains a problem that tends to ease in childhood 1,14,15 and adulthood. 7,8,16 Extreme prematurity 10,11,17 and being small for gestational age (SGA) 7,15,[18][19][20] are seen as specific risk factors in this growth lag.…”

Cerebral Palsy and Growth Failure at 6 to 7 Years

“…Linear growth is correlated with head/brain growth and subsequent neurodevelopmental outcome in infants and young children. 24 In addition, inadequate nutritional intake is associated with weakness of respiratory musculature, impaired cough reflex, and pneumonia. 25 Growth is an excellent indicator of the overall health of children and there are currently no data available on the growth outcomes of Mod/Sev HIE survivors in the era of hypothermia therapy.…”