Weaning of premature infants from the incubator to an open crib

Thirty pairs of healthy, growing preterm infants were included in this randomized prospective study comparing thermal weaning at 1700 g with that at 1800 g. Based on an intention-to-treat analysis, infants weaned at 1700 g were discharged 1.1 days sooner than those weaned at 1800 g. However, this result was not statistically significant (p = 0.13). On the other hand, differences are apparent between treatments in some strata based on birth weight (p = 0.0056). Evidence also existed that time from entry (at 1500 g) to discharge depended on birth weight stratum (p = 0.010). No infant in either group lost weight after successful weaning, and mean 24-hour weight gains were similar for both groups. Two infants were weaned at 1800 g requiring return to the incubator due to hypothermia, and four infants weaned at 1700 g likewise requiring return to the incubator. The number weaned at 1700 g who had birth weight of 1000 g or less and who developed hypothermia appeared substantial (three of six such infants). Thus, it appears that thermal weaning at 1700 g may be safe and effective only for prematures with birth weight above 1000 g. Additional study appears needed.