Prediction of fetal growth deviation by ultrasonic biometry. I. Methodology.

Early information of impaired or accelerated fetal growth is of importance for antenatal care. The present study has produced a mathematical formula which in the 33rd week of pregnancy permits prediction of fetal weight deviation at birth. The prediction was based on two ultrasonic examinations: in the 17th week of pregnancy the biparietal diameter (BPD) was measured to assess the fetal gestational age; in the 33rd week of pregnancy, BPD and the abdominal diameter (AD) of the fetus were measured. Fetal growth deviation was then described by comparing the assessed BPD and AD with the expected mean values for the gestational age on the day of this measurement. For 872 fetuses the growth deviation found in the 33rd week was related to the fetal weight deviation at birth; multiple regression analyses were performed and a mathematical formula developed. For practical purposes this formula is expressed in a nomogram.