Asymmetric intrauterine growth retardation: its association with preterm labor.

Premature newborns have been shown to have a lower birth weight than would be predicted from nomograms, suggesting an asymmetric pattern of intrauterine growth. The premature newborns of 95 patients were assessed for symmetry of growth utilizing the ponderal index (PI). Those patients were matched to 108 patients delivering at terms > 38 completed weeks. The PI determination of the preterm neonates was significantly lower than that of the term newborns, 2.31 +/- 0.35 versus 2.57 +/- 0.30, p < 0.001. These data suggest that fetuses delivered prematurely may have asymmetric patterns of intrauterine growth. Premature labor may alter normal substrate delivery to the fetus, producing an asymmetric weight-to-length ratio.