Birth outcome, not pregnancy process: reply to van der Veen.

In a recent article (Frisbie, Forbes, and Pullum 1996) we documented racial/ethnic differences in birth outcomes according to a more fine-grained classification than has typically been employed in the demographic literature. In his commentary, van der Veen focuses on the measurement of one of the dimensions of that classification, maturity of the infant, as proxied by the fetal growth ratio. The crux of the critique is easily seen in van der Veen's statement that "all of my disagreements with Frisbie et al.'s method arise from their particular use of a postnatal standard for the assessment of intrauterine growth." Our critic misunderstands our objective: He fails to realize our interest in birth outcome, not pregnancy process, and does not perceive that our intent was to extend the research extant in both the demographic and public-health literatures in which patently postnatal (i.e., ex utero) measures are taken as outcomes interesting in their own right and/or as risk factors for infant mortality and infant and childhood morbidity. Specifically, he does recognize that we purposefully expanded our focus to include moderately compromised births to determine if they were at higher risk than the normal births with whom they are conventionally categorized. Our discussion draws on research cited in the original article, on studies cited by our critic, and on a few more recent investigations. Although we have never argued that ours is the only, or even the best approach in all cases, we try to clarify the rationale for, and adduce additional empirical evidence of, the utility of the method we used.