Objectives: To describe birth-weight-for-gestational-age patterns by race, sex, and parity in
the United States population, and to discuss the measurements of gestational age by
different methods, the pitfalls of each method, and the potential effects of the errors on birth-
weight-forgestational-age curves. Methods: We used the computerized certificates of live
births from the entire population in 1989, consisting of more than four million infants born to
residents of the United States. Gestational age was based on the date of the last menstrual …