Objective: The present study was performed to evaluate the effect of nutrition on the thyroid function and urine iodine concentration in preterm and term newborns. Study Design: This prospective study inculuded all newborns admitted in NICU in 6 months period whose blood samples for neonatal screening were not collected. The neonates were divided into two groups as preterm and term. Infants with congenital malformation and history of maternal thyroid function disorders and maternal use of drug with iodine were not included. Plasma free T3 (FT3), free thyroxine (FT4), total T3, total T4, thyroid-stimulating hormone (TSH) and simultaneous urine iodine concentration in 5 ml spot urine were measured in 5-7 days of life. Other factors including amount of enteral and parenteral nutrition, feeding model (human milk and formula) and accompanying illness were recorded. Results: The study group was composed of 44 newborns inculuding 32 preterm and 12 term babies. The mean gestational age and mean birth weight of preterm infants were 31.9±2.4 weeks (range 26-37 weeks) and 1474±447 g (range 700-2450 g) respectively. The mean gestational age and mean birth weight of term infants were 38.9±0.9 weeks (range 38-40 weeks) and 3031±521 g (range 2400-4050 g) respectively. Plasma FT3, FT4 and T4 levels were found to be lower in preterm than term babies. The TSH and T3 levels were not found to be different in two groups. Amount of urine iodine was lower in preterm babies (p=0.003). Amount of urine iodine was significantly decresead in babies who were fed with parenteral nutrition (p: 0,017). Conclusions: This study confirms that thyroid hormone levels in preterm infants were much lower than term infants. The urine iodine level was found to be lower in preterm newborns especially who were fed with parenteral nutrition.
Key words: Newborn, premature, thyroid hormones, nutrition, urine iodine level
|
