Estimating fetal weights less than 2000 g: an accurate and simple method

Abstract
An accurate estimated fetal weight in the low-birth-weight infant can provide valuable information for the obstetrician faced with a decision concerning mode and time of delivery. Four existing equations for calculating fetal weight were analyzed and compared with data consisting entirely of infants with birth weights of 500-2000 g. A new formula, birth weight-grams = 10.1 (abdominal circumference-cm X biparietal diameter-cm) - 481, is proposed as a simple yet accurate alternative. This equation has a standard deviation of 99 g/kg.