Standard curves for birth weight

The standard curves based on data from Denver are used to determine whether birth weights are appropriate. Several reports note differences between their birth weights and those from the Denver report and ascribe them to climatic and socioeconomic conditions. This study analyzed the data for a middle-class city near sea level. The birth weights for two years (1970 and 1982) were analyzed. The 10th, 50th and 90th percentiles were provided for 36-44 weeks of gestation for the 1982 data. The birth weights increased significantly over time. A statistical analysis of proportions gave significance to the birth weight differences in terms of sex and parity. Part of the increase in cesarean sections might have been the result of the increase in birth weights. Standard curves for birth weights should be based on regional data and updated periodically.