Evaluation of carnitine deficit in very low birth weight preterm newborns small for their gestational age

Objective: To verify whether small-for-gestational-age (SGA) preterm newborns represent a special risk group for carnitine deficiency. Secondary outcome includes assessment of longitudinal differences of total carnitine (TC), free carnitine (FC) and acylcarnitines between SGA and appropriate-for-gestational-age (AGA).Methods: A retrospective study to evaluate carnitine and acylcarnitines profile on 144 very-low-birth weight newborns (VLBW), classified as AGA (n=73) and SGA (n=71), was performed by tandem mass spectrometry, during their first 5 weeks of life. Carnitine deficiency was defined as FC <40 mu mol/L and FC/TC <0.7.Results: Carnitine deficiency was observed in the two study groups throughout the monitoring period (maximum FC: 36.05 mu mol/L in AGA and 32.24 mu mol/L in SGA). FC/TC remains under 0.7 in both with progressive improvement. Unlike expected, a comparatively higher value of TC, FC and total acylcarnitines (tAC) was found in SGA during the first 2 weeks, with significant relevance on day 3-5, especially for tAC (p<0.001). The only acylcarnitine with persistently lower value in SGA is C5 (p<0.05 in first 2 weeks).Conclusions: A carnitine deficiency was demonstrated in all VLBW. Although birth weight restriction has been suggested as a risk factor for impaired carnitine status, in our study, SGA was not related with higher carnitine deficiency.