Postnatal growth curves for extremely low birth weight infants with early enteral nutrition

Early enteral nutrition improves growth of extremely low birth weight infants, but growth curves beyond 30 days of life are lacking for such infants receiving early enteral nutrition. Based on the data of all infants born in a 4-year interval with a birth weight <1000 g and surviving for >56 days, we calculated growth rates and weight gain over 120 postnatal days. Infants with major congenital anomalies or necrotising enterocolitis were excluded. Daily weight, weekly length, head circumference and nutritional data were collected until discharge or for maximal 120 days. Curves were calculated in 100 g birth weight intervals, and separately for appropriate for gestational age (AGA) and small for gestational age (SGA) infants. Data were available from 163 infants (birth weight 768 g +/- 153 g; gestational age 26.8+/-1.8 weeks; mean +/- SD) including 55 SGA infants (33.7%). Full enteral feeding was achieved at day 21.7 (+/-10.4). After 12.8% (+/-6.6%) maximal postnatal weight loss at day 7.5 (+/-3.0), birth weight was regained at 14.6 (+/-6.0) days. Mean overall weight gain was 15 g/kg per day with a significantly higher weight gain for SGA than for AGA infants (P <0.05).

Our early fed infants achieved better weight gain than those recently published receiving late enteral nutrition, but nevertheless fell below the 10th percentile of intrauterine curves. Which postnatal growth is ideal for extremely low birth weight infants infants is unclear. Our growth curves should not be taken as reference curves of a "normal population" but may help to identify infants with growth failure.