A hypothetical model suggesting suboptimal intrauterine growth in infants delivered preterm.

Infants delivered preterm often reflect accelerated maturation. The present study examines the occurrence of suboptimal intrauterine growth in infants delivered preterm by comparing their birth weights to the weights sonographically predicted for in utero fetuses at similar gestational ages but who ultimately deliver at term. Two weight-predicting formulas based on different sonographic parameters were used. In the fifth, tenth, and 50th percentiles of birth weight, the predicted weights were persistently and significantly greater than the actual birth weights between 24 and 31 weeks' gestation. The results of this model support the concept that the growth of infants delivered prematurely has been suboptimal. The authors hypothesize that preterm delivery may be in some instances another manifestation of the same underlying stress that hastens pulmonary and neurologic maturity.