Early postnatal growth in preterm infants.

Changes in weight of 50 preterm infants (gestational age 32.7 +/- 0.3 weeks, birthweight 1772 +/- 49 g) were studied during the period of the 0-4 postnatal weeks. Intrauterine weight gain of fetuses with equivalent gestational age, weight percentile position and sex was calculated and used as a control. Study infants achieved significantly less weight by age of 4 weeks (116.2 +/- 1.2%) than it could have been expected theoretically (144.7 +/- 1.0%). Growth performance did not correlate significantly with calorie intake, but was closely related with gestational age.