Editors: MYRON E. WEGMAN, M.D..
SURVIVAL of premature infants, even with the best of care, is conditioned by intrinsic factors of which the single most important is stage of maturity. In practice, the objective measure of maturity is weight at birth, although relation between weight and maturity is affected very strongly by factors such as sex, race, socio-economic status and whether or not the birth was plural. It has been amply demonstrated that at a given weight at birth, female babies are more mature than males, Negro babies (at least in the U.S.A.) are more mature than white, children born to parents of lower socio-economic status more mature than those of the higher levels, and plural births more mature than single births. Thus it follows for race, in the U.S.A., as an example, that, regardless of care given, a Negro baby of, for instances, 1800 grams would have a distinctly greater chance of survival than a white baby of the same weight. The same observation is true for the other factors cited. Clearly it is impossible to compare statistics for one group of premature infants and another unless the experience of each sub-group is compared individually or some statistical means is taken to compensate for differences in composition. Several modifications of the technique of statistical standardization have been proposed for the latter although it has been the opinion of this editor that a simpler approach might be focusing attention on specific rates for white and Negro babies, separately, in one or two weight groups, e.g., 1500 to 2000 grams.