Correlation of Weight Estimation in Large and Small Fetuses with Three-Dimensional Ultrasonographic Volume Measurements of the Fetal Upper-Arm and Thigh: A Preliminary Report
Somsak Patipanawat MD*, Ratana Komwilaisak MD**, Thawalwong Ratanasiri MD**
Affiliation : * Department of Obstetrics and Gynecology, Khon Kaen Regional Hospital, Khon Kaen ** Division of Fetal Diagnosis and Therapy, Department of Obstetrics and Gynecology, Faculty of Medicine, Khon Kaen University, Khon Kaen
Objective : To determine the correlation of measuring fetal upper-arm and thigh volume using three-dimen-
sional ultrasonography with weight estimation in large and small fetuses.
Materials and Methods : The authors included 46 pregnant women admitted for delivery in the Labor Room at
Srinagarind Hospital, Khon Kaen University, between February 1 and September 30, 2004. Inclusion criteria
were: 1) singleton pregnancy; 2) delivery within 48 hours after study; 3) estimation birthweight < 2,500 g
(small fetuses group: n = 22) or > 3,500 g (large fetus group: n = 24). All patients received two- and three-
dimensional ultrasound examinations by an experienced practitioner. The upper-arm and thigh volume were
assessed using a three-dimensional ultrasound scanner.
Results : In the large fetus group, upper-arm and thigh volume measurements by three-dimensional ultrasound
strongly correlated with birthweight, r = 0.805 (95%CI = 0.594-0.912) and r = 0.739 (95%CI = 0.478-0.880),
respectively. In the small fetuses group, the upper-arm and thigh volume measurements, by three-dimensional
ultrasound, strongly correlated with birthweight, r = 0.868 (95%CI = 0.689-0.946) and r = 0.835 (95%CI =
0.638-0.929), respectively.
Conclusion : Upper-arm and thigh volumes measured by three-dimensional ultrasound highly correlates with
weight estimation in large and small fetuses and can be used as a new modality for estimating fetal weight.
Keywords : Upper-arm volumes, Thigh volumes, Birthweight estimation by three-dimensional ultrasound, Large fetuses and small fetuses
