Screening efficacy of the subcutaneous tissue width/femur length ratio for fetal macrosomia in the non‐diabetic pregnancy

• Published in: Ultrasound in obstetrics & gynecology Vol. 13; no. 5; pp. 340 - 344
• Main Authors: Rotmensch, S., Celentano, C., Liberati, M., Malinger, G., Sadan, O., Bellati, U., Glezerman, M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-05-1999; Wiley
• Subjects: Adolescent; Adult; Anthropometry; Biological and medical sciences; Diseases of mother, fetus and pregnancy; Embryonic and Fetal Development - physiology; Female; Femur - diagnostic imaging; Femur - growth & development; femur length; Fetal Macrosomia - diagnosis; Fetal Macrosomia - diagnostic imaging; Gestational Age; Gynecology. Andrology. Obstetrics; Humans; Infant, Newborn; macrosomia; Male; Mass Screening - methods; Medical sciences; Predictive Value of Tests; Pregnancy; Pregnancy Trimester, Third; Pregnancy. Fetus. Placenta; Prenatal Care; ROC Curve; screening; Sensitivity and Specificity; Skin - diagnostic imaging; Skin - growth & development; subcutaneous tissue width; Ultrasonography, Prenatal; Italy; Europe; Sonography; Performance evaluation; Human; Femur; Pregnancy disorders; Length measurement; Macrosomia; Thickness measurement; Prenatal; Fetal diseases; Malformation; Echography; Fetus; Diagnosis; Subcutaneous tissue
• ISSN: 0960-7692; 1469-0705
• DOI: 10.1046/j.1469-0705.1999.13050340.x

Background
Antenatal weight estimations have limited sensitivity and specificity for the detection of macrosomia. The objective of our study was to examine the screening efficacy of the subcutaneous tissue width/femur length ratio for the intrapartum detection of fetal macrosomia in a non‐diabetic population at term.
Study design
Intrapartum sonographic measurements were performed in 178 well‐dated gravidas at 37–41 weeks' gestation with negative glucose tolerance screens. The biparietal diameter, femur length (FL), abdominal circumference and subcutaneous tissue width of the thigh (SCT) were determined. Subsequently, predictions for macrosomia (actual birth weights above the 90th centile) were made using varying cut‐off points of the examined parameters or estimated fetal weights.
Results
Macrosomia occurred in 27 newborns (15.1%). The SCTFL ratio was independent of gestational age (r = −0.017). Maternal age, gravidity, parity, gestational age and the ratio of male‐to‐female infants were similar in pregnancies resulting in appropriate‐for‐gestational‐age and macrosomic infants (NS). There was no difference in the SCT/FL ratio between these groups (p = 0.067; 99% power to detect 2 standard deviation differences). Comparison of screening efficacy by the univariate z score for the area under receiver operating characteristic (ROC) curves (θ) revealed that the abdominal circumference had the best sensitivity‐specificity trade‐off (θ = 0.8843; p < 0.0001 for comparison with SCT/FL ROC curve), followed by weight estimations based on the Hadlock formula (θ = 0.8773; p < 0.0005), the Shepard formula (θ = 0.8606; p < 0.0001), subcutaneous tissue thickness alone (θ = 0.6872; p < 0.01) and the SCT/FL ratio (θ = 0.6303).
Conclusions
We conclude that the SCT/FL ratio is a poor sonographic predictor of fetal macrosomia in the non‐diabetic pregnancy and does not improve fetal weight estimations by conventional sonographic parameters. Copyright © 1999 International Society of Ultrasound in Obstetrics and Gynecology