Predictive value of the femur length to abdominal circumference ratio in the diagnosis of intrauterine growth retardation.
The ratio between sonographically measured fetal femur length to abdominal circumference (F/A) was studied in 471 consecutive normal singleton pregnancies from 18 to 40 weeks' gestation. The 90th (0.2715) percentile of this ratio was evaluated as a predictor for intrauterine growth retardation (IUGR) in an additional 1,502 pregnant women; 146 fetuses were found to be above the 90th percentile, of which 20 were born growth retarded. A total of 69 fetuses was found post partum to be small for date; 44 were asymmetrically growth retarded and 25 were symmetrically growth retarded. Of the 20 growth-retarded fetuses, which were correctly diagnosed in utero, 19 were asymmetrically growth retarded. The additional 49 growth-retarded newborns were not detected using the F/A ratio as a diagnostic parameter. Low sensitivity (29.98%) together with low positive predictive value (13.69%) rendered the parameter unsuitable for screening IUGR. Nevertheless, the high specificity (91.20%), together with the high negative predictive value (96.38%), makes it a useful age-independent parameter in high risk pregnancies, where asymmetric IUGR is suspected.
Shalev
E
E
Department of Obstetrics and Gynecology, Central Emek Hospital, Afula, Israel.
Romano
S
S
Weiner
E
E
Ben-Ami
M
M
D000005:Abdomen / Q000000981:diagnostic imaging*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D011237:Predictive Value of Tests; D011247:Pregnancy; D011296:Prenatal Diagnosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography