Estimation of fetal weight by ultrasound prior to 33 weeks gestation.
The aim of this study was to develop an accurate formula for the ultrasonic prediction of fetal weight for infants < 33 weeks gestational age and < or = 1500 g birthweight. The subjects comprised live births free of lethal malformations or chromosomal anomalies, < 33 weeks gestational age and with birthweights +/- 1500 g born in the Royal Women's Hospital between January 1990 and March 1996. All subjects had accurate gestational age confirmed by ultrasound prior to 20 weeks gestation and ultrasound measurements within 72 hours of birth of biparietal diameter (BPD), femur length (FL) and abdominal circumference (AC). A formula with the highest explained variance was computed by linear regression analysis using the three fetal variables in various combinations from 54 infants born between January 1990 and December 1993. The optimal formula was: Log(10)birthweight = 0.714627 + 0.077362.AC + 0.058758.BPD + 0.287037.FL - 0.011274.AC.FL. The new formula was more accurate compared with existing formulae when tested in a separate cohort of 39 infants born between January 1994 and March 1996.
Division of Maternity Services, The Royal Women's Hospital and University of Melbourne, Victoria, Australia.
A
A
Hotchin
R
R
Bell
M P
MP
Umstad
H P
HP
Robinson
L W
LW
Doyle
D015331:Cohort Studies; D005260:Female; D020567:Fetal Weight; D006801:Humans; D007231:Infant, Newborn; D016014:Linear Models; D011237:Predictive Value of Tests; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D016216:Ultrasonography, Prenatal / Q000592:standards / Q000706:statistics & numerical data*