Birth Weight and Gestation As Indices of "Immaturity"

THE CONCEPT of prematurity has evolved over the years and expanded beyond the intuitive notion of a pregnancy which terminates before term. Currently it assumes more nearly the connotation of a pregnancy which terminates before the fetus derived the benefit of full and satisfactory intrauterine development. It is, thus, not limited to pregnancies which terminate early—it implies, rather, that the fetus did not develop in utero long enough or well enough. For purposes of investigating the phenomenon of prematurity, it is therefore not sufficient to employ an index of "length of pregnancy." It is desirable to utilize also an index of "adequacy of intrauterine development." It is difficult to formulate a satisfactory objective index of adequacy of intrauterine development since the fetus can be observed and evaluated only after the pregnancy terminates. One must therefore rely primarily on extrauterine measures and yardsticks. The anthropometric measurements of weight, of length, and