Lack of effect of L-carnitine supplementation on weight gain in very preterm infants

Objective: Carnitine transfer across the placenta occurs predominantly during the third trimester. Unless L-carnitine is provided, very preterm infants develop carnitine deficiency. Although breast milk and infant formulas contain L-carnitine, parenteral nutrition solutions do not routinely provide L-carnitine. We hypothesized that prolonged L-carnitine supplementation in very preterm infants would improve weight gain and shorten length of stay in the hospital. Study design: The study was a double-blind parallel placebo-controlled randomized clinical trial. Eligible patients were <29 weeks of gestation, <72 hours of age, and did not have a potentially life-threatening congenital malformation or hereditary metabolic disorder. Patients were stratified by gestational age (23 to 25^6/7 and 26 to 28^6/7 weeks), and randomized to receive, either L-carnitine at a dose of 50 μmol/kg/day, or placebo. Carnitine was provided intravenously until the infants tolerated 16 ml/day of feeds. The sample size was calculated to have 80% power to detect a 10% increase in weight gain from birth until 36 weeks of postmenstrual age or discharge from the hospital. Secondary outcome variables included food efficiency (defined as weight gain divided by caloric intake), weight gain at 4 weeks of age, time to regain birth weight and length of stay. Results: Among the 63 infants enrolled in the trial, 32 were randomized to L-carnitine and 31 to placebo. L-Carnitine supplementation did not significantly affect average daily weight gain from birth until 36 weeks or hospital discharge, or any of the secondary outcome variables. Conclusion: Prolonged supplementation of L-carnitine did not improve long-term weight gain in very preterm infants.