[Growth of preterm newborns during the first 12 weeks of life].

OBJECTIVE To assess the somatic growth of preterm newborns through growth curves during the first 12 weeks of life. METHOD A longitudinal and prospective study was carried out at two state operated maternity hospitals in the city of Belo Horizonte. Three hundred and forty preterm infants with birth weight less than 2,500 g were weekly evaluated in terms of body weight, head circumference, and height. Growth curves were constructed and adjusted to Count's model. RESULTS Count's model clearly showed that the dynamics of loss, stabilization and gain of weight of all curves are graphically similar. The growth curve was characterized by weight loss during the 1st week (4-6 days) ranging from 5.9 to 9.7% (the greater the percentage, the lower the birth weight). For all curves, recovery of birth weight ranged from 16 to 19 days, showing that these newborns took longer to recover their birth weight. After the 3rd week, the newborns maintained increasingly rates of weight gain. Head circumference and height curves are little affected by weight loss. However, newborns with low birth weight presented loss of head circumference and height, probably due to their lower gestational ages. CONCLUSION The dynamics of the preterm infants evaluated was similar to that of previous studies. The infants also presented growth deficit. However, it was also noted that the infants present a high potential to recover their growth.