Weight gain in exclusively breastfed preterm infants.

The weight gain of 355 preterm low birth weight infants, who were exclusively breastfed by their own mothers after discharge from the special care nursery, was analysed prospectively over the first 24 weeks of infancy. Preterm infants with birth weights of 1000-1500 g significantly doubled their birth weight by 10 weeks of age and tripled it by 18 weeks, with a growth velocity of 20-30 g/day up to 20 weeks of age. Preterm infants with birth weights of 1501-2000 g doubled their birth weight by 12 weeks of age and tripled it by 16 weeks, with a growth velocity of 30 g/day up to 11 weeks and 20 g/day after the 12th week. Preterm infants born at 32 weeks gestational age had a period of growth delay up to 3 weeks of age followed by a brisk catch-up phase, whereas infants born at 34 and 36 weeks gestational age had a shorter period of growth delay of 2 weeks followed by a similar catch up phase. The weights attained were comparable to intra-uterine growth rates.