Normal growth of the abdominal perimeter.

The value of the computed abdominal perimeter has been studied in a cross-sectional study of 850 fetuses and in a longitudinal study of 46 fetuses (695 examinations). Our computed values differ from values reported for measured abdominal perimeter. The ratio of the abdominal perimeter to the femur length is proposed as a new parameter to assess fetal well-being. The advantages of this ratio-ease of computation, independence of gestational age, use of common and easily accessible parameters--are discussed. Nomograms of the values are provided.